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Honda Jazz Forums => Honda Jazz Mk2 2008-2015 => Topic started by: guest5044 on October 06, 2014, 09:09:07 PM

Title: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5044 on October 06, 2014, 09:09:07 PM
Hi all

First post, so please be gentle...

My neighbour has a 2010 Jazz 1.4 Si, which as standard has 16" alloy wheels with 185/55/16 83H tyres.

As I did for his previous generation Jazz that he's recently replaced, I've offered to find out what winter wheels/tyres will fit, so he can order some. Unfortunately the 14" wheels off the previous car won't fit.

I'm looking at what steel wheel sizes would be acceptable.

Mytyres and Oponeo are suggesting the following wheel size:
5.5Jx15
4x100 PCD
45mm offset
56.1mm centre bore

...with the following tyre size:
175/65 R15 84H

The tyre sizes looks bang on, rolling circumference is only 1mm different from the original size.

Can anyone confirm if this wheel & tyre size is suitable for a 2010 Jazz 1.4 Si ?
Does the manual state anything about acceptable winter wheel/tyre sizes ?


Many thanks in advance  :)
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on October 06, 2014, 09:26:13 PM
http://clubjazz.org/forum/index.php?topic=4960.15 (http://clubjazz.org/forum/index.php?topic=4960.15)

read the above thread about winter tyres

i recently bought the 175 R15 Nokian winter tyres and 5-1/2 J steel wheels from mytyres for my wifes Jazz GE Si and can confirm they fit no problem, and the wheel clears the brake calipers etc.,  and you can use same domed wheelnuts from alloys.

there is a 'link' (it just says link) at the bottom of one of my replies- it takes you to mytyres site and to the wheel / tyre combination I purchased.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5044 on October 08, 2014, 12:28:04 PM
Great, many thanks for that, much appreciated  :)

Does it mention anything about wintyer wheel/tyre sizes in the handbook ?
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5042 on October 08, 2014, 01:13:13 PM
I used to have winter and summer tyres
Having got the jazz I am opting for All season tyres as the technology has improved greatly in recent years - and no tyre changes
I have gone for Falken but there are many good ones out there
Search for auto bild all season 2013 test for more info
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: apjazz on October 08, 2014, 01:27:47 PM
I think he offset for correct wheels is 53 not 45 - but look on inside wheels it is stamped/cast there.

Fit the same as supplied, the wheel setup could change over/under steer characteristics and maybe inform insurance if changing.

It seems to me too many 'experts' change these basic car design features with no mention of consequences.

Honda dealers often offer a 15" wheel and suggest a tyre that has approximately the same outside diameter as the 16"tyre/wheel combination which has indeed got 45 offset, fundamentally incorrect to do so from so many aspects.

Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on October 09, 2014, 07:30:18 PM
I think he offset for correct wheels is 53 not 45 - but look on inside wheels it is stamped/cast there.

Fit the same as supplied, the wheel setup could change over/under steer characteristics and maybe inform insurance if changing.

It seems to me too many 'experts' change these basic car design features with no mention of consequences.

Honda dealers often offer a 15" wheel and suggest a tyre that has approximately the same outside diameter as the 16"tyre/wheel combination which has indeed got 45 offset, fundamentally incorrect to do so from so many aspects.

These are the rim details of the ones I purchased from mytyres for my wifes GE 1.4 Si and they fit beautifully.  Outside diameter with  175/65  R15 is the same as  original 185/55 R16 setup on Si.

Rim type   4-hole steel wheel
Size   5˝ x 15
Bolt pattern   4 x 100.00 x 56.00
Offset   45.00

Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest4078 on October 09, 2014, 11:29:33 PM
Honda Jazz steel wheels, 14" or 15" any model from 2002:

    Offset: 45.00
    PCD: 4x100
    Central bore: 56.1

 You could offset a little less but a higher offset of 53 is too much. It would give 7-8 mil less clearance to struts and might require spacers.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: apjazz on October 11, 2014, 10:18:17 PM
From AA
If you follow the standard European practice of keeping two sets of wheels, one with winter tyres and one with summer tyres, then you shouldn't need to tell your insurer as long as the winter tyres are fitted to wheels of the correct specification.
'Correct specification' means that the wheel size – diameter, width and offset – conforms to the vehicle manufacturer's specifications.
Check the handbook for details of wheel/tyre sizes suitable for your car and refer to the car manufacturer or dealer for further advice.
Association of British Insurers (ABI) Statement

Motor insurers recognise that some motorists may wish to fit winter tyres to their car during cold weather. Motor insurers recognise that, whilst no substitute for common sense driving, winter tyres can have a positive impact on improving road safety.

To assist in reducing potential uncertainty, the ABI has produced a commitment setting out the position of a number of named motor insurers in respect of the impact on insurance premiums of fitting winter tyres to your car.

It's important to check the list of insurers as some require that you inform them if winter tyres are fitted even though there is no effect on premiums or cover.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: Eddie Honda on October 11, 2014, 11:58:36 PM
From the "ABI guide to winter tyres The motor insurance commitment" mentioned above:

WINTER TYRES – THE MOTOR INSURANCE COMMITMENT

Motor insurers recognise that some motorists may wish to fit winter tyres to their car during cold weather. Motor insurers recognise that, whilst no substitute for common sense driving, winter tyres can have a positive impact on improving road safety. In the past there has been some uncertainty for insured customers about the insurance premium implications of fitting winter tyres to their cars. To assist in reducing this potential uncertainty, the ABI has produced the Commitment set out below which sets out the position of those named motor insurers in respect of the impact on the insurance premiums of their insured customers if a customer wishes to fit winter tyres to their car.

As can be seen, often motor insurers will not charge an additional premium when their insured customers use winter tyres, provided that they meet, and are fitted in accordance with, the vehicle manufacturers’ specifications and are in a roadworthy condition.

However, some motor insurers may require you to contact them to let them know if you do choose to fit winter tyres. The name of your insurer and their contact information can be found on your insurance policy documentation (summary details are provided below). It is important to remember that sometimes your motor insurer may be different from the company that sold you your insurance policy.

This Confirmation will apply from 3rd September 2014 to 2nd September 2015 at which time it will be reviewed.

Please note that this Commitment only applies to cars used for personal use that are insured under a private or personal use car insurance policy.

The commitment of insurers:

The insurers named below do not require the payment of any additional premium if customers decide to fit winter tyres to their cars, provided that the tyres meet, and are fitted in accordance with, the relevant vehicle manufacturers’ specifications and are in a roadworthy condition whilst in use.



InsurerDo customers need to inform the insurer when fitting winter tyres to their cars?Does the fitting of winter tyres affect the amount of cover provided to customers?Contact details
1st Central InsuranceNoNo
ABC InsuranceNoNo
Acromas Insurance Company Ltd No - unless the dimensions of the tyres fitted do not meet the manufacturer's standardNo - unless the dimensions of the tyres fitted do not meet the manufacturer's standardYour policy documentation will have the contact details of your intermediary
AdmiralNoNo
Adrian FluxNoNo
Advantage Insurance Company Limited (Gibraltar)NoNo
Age UKNoNo
Ageas Insurance LtdNoNo
Aioi Nissay Dowa InsuranceNoNo
AllianzNoNo
Allianz (Northern Ireland)NoNo
Allianz Your CoverNoNo
Aviva InsuranceNoNo
AXANoNo As per policy documentation (varies by distribution channel)
BellNoNo
Chaucer DirectNoNoShown on website
ChurchillNoThe fitting of winter tyres will not affect the amount of cover provided0845 603 3551
CitroenNoThe fitting of winter tyres will not affect the amount of cover provided0870 024 2730 / 0870 125 6616
Collingwood Insurance Company LtdNoNo, provided the winter tyres/wheels fitted are of no greater size value than the tyres/wheels being replaced
Co-operative Insurance Car InsuranceNoNo, provided the winter tyres/wheels fitted are of no greater size or value than the tyres/wheels being replaced
Co-operative Insurance Eco InsuranceNoNo, provided the winter tyres/wheels fitted are of no greater size or value than the tyres/wheels being replaced
Co-operative Insurance Young Driver InsuranceNoNo, provided the winter tyres/wheels fitted are of no greater size or value than the tyres/wheels being replaced
Cornish MutualNoNo
CoveáInsuranceNoNo
DiamondNoNo
Direct LineNoThe fitting of winter tyres will not affect the amount of cover provided
Drive SmartNoNo change to cover provided
eCar Yes, by phone or emailNoenquiries@ecarinsurance.co.uk
EchoiceNoNo
EggNo The fitting of winter tyres will not affect the amount of cover provided0870 024 0095 / 0870 024 0097
ElephantNoNo
Enterprise No - Unless the dimensions of the tyres fitted do not meet the manufacturer's standard specification No, provided the winter tyres/wheels fitted are of no greater size value than the tyres/wheels being replacedRefer to Insurer via their Insurance Broker, who can refer to the insurer via email Underwriting@eigplc.com
ERSNoNo
Esure Car Insurance No - unless the customer has or is fitting alloy wheelsNoPhone: 0845 603 7874
First Alternative Car Insurance No - unless the customer has or is fitting alloy wheelsNoPhone: 0845 607 0417
General Motors (Vauxhall & Chevrolet)NoNo
Go GirlNoNo change to cover provided
Groupama InsurancesNoNo
Highway InsuranceNoNo
Hiscox Insurance CompanyNoNo
Insure2DriveNoNo change to cover provided
KGM/Canopius No (provided they adhere to the stated commitment & tyres are fitted to the manufacturer’s instructions & are in a roadworthy condition)No
Lexus Motor InsuranceNoNo
LV =NoNo
MarkerstudyNoNo
Mint / MBNANoThe fitting of winter tyres will not affect the amount of cover provided0870 024 0138
MORE TH>NNoNo
NatwestNoThe fitting of winter tyres will not affect the amount of cover provided0800 051 0289 / 0800 051 5405
NFU MutualNoNo
Octagon Insurance Company LimitedNo – provided the winter tyres/wheels match the sizes fitted by the vehicle manufacturer as either standard fitment or as an optional extraNo – provided the winter tyres/wheels match the sizes fitted by the vehicle manufacturer as either standard fitment or as an optional extra Customers who wish to contact Octagon can call Customer Service on 0844 561 4615
PeugeotNoThe fitting of winter tyres will not affect the amount of cover provided0870 024 0807 / 0870 024 1107
Premier InsuranceNoNo
PrivilegeNoThe fitting of winter tyres will not affect the amount of cover provided0800 061 6990 / 0800 051 6990
PrudentialNoThe fitting of winter tyres will not affect the amount of cover provided0800 300 300 / 0845 605 9260
QBENoNo
RBSNoThe fitting of winter tyres will not affect the amount of cover provided0800 158 2493 / 0845 246 0453
Royal LondonNoThe fitting of winter tyres will not affect the amount of cover provided0800 032 9455
RSANoNo
Sabre Insurance Co LtdNoNo change to cover provided
Sainsbury’s Car Insurance (underwritten by esure insurance up to 31.05.2011)No - unless the customer has or is fitting alloy wheelsNoPhone: 0845 608 6034
Sainsbury’s Car Insurance (underwritten by UK Insurance from 01.06.2011)NoThe fitting of winter tyres will not affect the amount of cover providedPhone:
Service UnderwritingNoNo
Shearwater InsuranceNoNo
Sheilas' Wheels Car InsuranceNo - unless the customer has or is fitting alloy wheelsNoPhone: 0845 604 3550
Southern Rock InsuranceYes, by phone or emailNoEmail: referrals@sricl.com
Phone: 0844 902 9749
SwiftcoverYesNo As per policy documentation (varies by distribution channel)
Tesco Underwriting Limited (for Tesco Car Insurance policies underwritten by Tesco Underwriting Limited)NoNo
Toyota Motor InsuranceNoNo
UKINoThe fitting of winter tyres will not affect the amount of cover providedContact details can be found via the intermediary
USAA LimitedNoNo
ZenithNoNo
Zurich Car SolutionsNoNo
Zurich Car Insurance (Direct)NoNo
Zurich Car Solutions (Broker)NoNo
Zurich CommercialNoNo
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: apjazz on October 13, 2014, 01:17:51 PM
It should be borne in mind also for those who may consider changing wheels/tyres from 16" to 15" with different offsets because other Jazzes uses such s/tyres that the track widths (front and rear) of (2007-2014) cars supplied from Honda with 15" wheels is different from that supplied with 16" wheels.
So you are in fact messing with design details that set up the car and has been tested to be safe!

Ask Honda to give you an approval to make such changes, unless just keep it simple and use the correct equipment.

Track 15 inch wheel model   Front   1,490 mm (58.7 in.) Rear   1,475 mm (58.1 in.)      
16 inch wheel model   Front   1,475 mm (58.1 in.)   Rear   1,460 mm (57.5 in.)      
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on October 13, 2014, 09:29:06 PM
It should be borne in mind also for those who may consider changing wheels/tyres from 16" to 15" with different offsets because other Jazzes uses such s/tyres that the track widths (front and rear) of (2007-2014) cars supplied from Honda with 15" wheels is different from that supplied with 16" wheels.
So you are in fact messing with design details that set up the car and has been tested to be safe!

Ask Honda to give you an approval to make such changes, unless just keep it simple and use the correct equipment.

Track 15 inch wheel model   Front   1,490 mm (58.7 in.) Rear   1,475 mm (58.1 in.)      
16 inch wheel model   Front   1,475 mm (58.1 in.)   Rear   1,460 mm (57.5 in.)      


I don't think that 0.5" (6mm per side)  is going to make any difference to the car at all.   I am more than happy to change from 16" to 15" wheels for the winter,  the outside diameter of the 15" tyre is within 1mm of the 16" (which is all I would worry about if it was going to affect the speedometer reading). My wife will hardly be pushing the car to the limit during the winter,  even in the summer she drives at the same speed as a snail with a wooden leg.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5059 on October 14, 2014, 06:54:09 AM
I've recently got a 2012 1.2 se stop start Jazz and have changed the tyres to have summer tyres on the front winter ones in the rear. And reverse at the end of Oct to have winter ones on the front.  They're vredstein on standard 15 inch steel wheels , 175/65 I think

Sent from my XT1052 using Tapatalk

Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: apjazz on October 14, 2014, 12:06:27 PM
6mm per side not making a difference?????????????
- I think you should contact Honda and tell how much time and money they waste by having Engineers design cars, if the differences were not necessary them a mass produced product like cars would not have them!
Maybe even consider bearing loads being changed let alone the handling characteristics of the car, - maybe slight for normal use but Honda wouldn't waste the money making these differences unless it is required,

Also mixing winter and summer tyres - a definite no no from handling point of view, please refer to AA site!
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest4078 on October 14, 2014, 05:24:11 PM
Isn't the difference taken up by the alternate specs of tyre, 175 v 185 as oe.
16" will be wider on the road than 15"?

Please do not mix 'winter' and 'summer' tyres this will put the handling in the ditchfinder class, quite skittish!
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest4324 on October 19, 2014, 12:28:48 PM
 You can fit 15" wheels with 175/65R15 winter tyres on an offset of 45 no problem, this is the definite correct size. I have 16" 185/55R16 alloys as standard and have the above mentioned winter tyres on steel wheels. In Switzerland and EU you can buy either size wheel for any model Jazz (2009 - ) direct from Honda (and I'm sure in the uk as well), the tracking dimension is coming from the wheels with tyres fitted, and therefore varies slightly depending on the tyre size, and has no effect on safety, it has been tested with both tyre sizes fitted, just like any other car manufacturer that offers various wheel sizes for one particular model.
 Personally, I would not buy all weather tyres because you will always have a compromise somewhere. And like a few others have said, do not mix summer and winters, it is even illegal here.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on October 19, 2014, 01:02:16 PM
Isn't the difference taken up by the alternate specs of tyre, 175 v 185 as oe.
16" will be wider on the road than 15"?

Please do not mix 'winter' and 'summer' tyres this will put the handling in the ditchfinder class, quite skittish!


I agree completely - it is very dangerous to mix winter and summer tyres as the rubber compound and tread pattern and construction are different.  The level of grip on winter tyres is better than summer tyres on colder road surfaces (generally below 7 to 10 deg C) but actually worse on warmer roads.  This is partly due to softer compound, but mainly due to the many extra 'sipes' (intentional cuts) in the tread on winter tyres which affect the stability of the tread blocks during braking - which can increase stopping distance in warmer conditions.

Mixing summer and winter tyres can give extra grip on one end of the car under either warm or cold conditions, as Interlock quite rightly points out - this can de-stabilise the cars handling to a dangerous degree.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5059 on October 19, 2014, 04:49:18 PM


Isn't the difference taken up by the alternate specs of tyre, 175 v 185 as oe.
16" will be wider on the road than 15"?

Please do not mix 'winter' and 'summer' tyres this will put the handling in the ditchfinder class, quite skittish!


I agree completely - it is very dangerous to mix winter and summer tyres as the rubber compound and tread pattern and construction are different.  The level of grip on winter tyres is better than summer tyres on colder road surfaces (generally below 7 to 10 deg C) but actually worse on warmer roads.  This is partly due to softer compound, but mainly due to the many extra 'sipes' (intentional cuts) in the tread on winter tyres which affect the stability of the tread blocks during braking - which can increase stopping distance in warmer conditions.

Mixing summer and winter tyres can give extra grip on one end of the car under either warm or cold conditions, as Interlock quite rightly points out - this can de-stabilise the cars handling to a dangerous degree.

This also applies to anybody that has different makes of tyres whether they are on the front , rear or even on the same axle. Mine are all the same make 175/65 R15 84T summer and M&S. You need to also give the same advise to those that have different makes of tyres ( that will mean different compound , tread and performance )fitted of which there are lots.


Sent from my XT1052 using Tapatalk

Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest5121 on November 17, 2014, 06:04:19 PM
Hey all,
Our Jazz has got a set of 185/65-15 winter tyres with spikes on oem steelwheels, runs nice and smooth, does not rub and gives you a bit longer gearing so, it should be good for motorway cruising.
We had 175/65-15 on stock alloys for summer, but for 2015 summer plans are going to get set of 16".
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on November 29, 2014, 05:20:01 PM
Hey all,
Our Jazz has got a set of 185/65-15 winter tyres with spikes on oem steelwheels, runs nice and smooth, does not rub and gives you a bit longer gearing so, it should be good for motorway cruising.
We had 175/65-15 on stock alloys for summer, but for 2015 summer plans are going to get set of 16".

it may have longer gearing but your speedo is now displaying about 7% lower speed than you are actually traveling at,  may result in a speeding ticket one day soon.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest3521 on November 30, 2014, 09:58:29 PM
it may have longer gearing but your speedo is now displaying about 7% lower speed than you are actually traveling at,  may result in a speeding ticket one day soon.

I'm not sure where you get 7% from?, the tyre calculator I use gives a difference in diameter of 2.14% and a speed difference of -2.09% (slower), this may differ very slightly with the make of tyre.
In my experience it would make the speedometer read a bit more accurately as they always read too fast from the factory.
FWIW I'm now running 185/65 15 winter tyres, and have not noticed that big a difference, however I will check it against my GPS's and report back.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: VicW on December 01, 2014, 03:19:37 PM
In my experience it would make the speedometer read a bit more accurately as they always read too fast from the factory.

For what it's worth, on all three of the Jazz's that I have owned the speedometers were very accurate compared with my satnav indicated speeds.

Vic.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on December 02, 2014, 06:21:44 PM
http://tire-size-conversion.com/tire-size-comparison/ (http://tire-size-conversion.com/tire-size-comparison/)

according to this site the difference between a 15" 185/65  and 15"  175/65 is over 6%

difference between a 15"  185/55 and a 14" 175/65 is basically nothing,  that is why it's OK to fit the 14" 175/65 winter tyres to a Jazz Si etc that normally take 15" 185/55 tyres
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest4477 on December 02, 2014, 10:01:39 PM
Hi,i must agree with what Vic as said my Sat-nav and speedo are always spot on the same regardless of what speed i am doing,2007 Honda 1.4
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest3521 on December 14, 2014, 11:55:24 AM
OK, so I've checked my speedo/OBD/gps and the results are as follows, 65mph indicated on speedo, cruise control set, OBD reading 62mph, 63mph on GPS, as a comparison the standard 185/55R16's the OBD and GPS are the same, so yes there is a slight difference, but not enough to make the speedo slow/low.

Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: stiggysawdust on December 14, 2014, 03:21:46 PM
As a retired truck driver, I can verify that Tachographs fitted to trucks are very accurate and they always agreed with my GPS.
When the same GPS unit is used in my jazz it always give a different reading to the Jazz speedo.
At an indicated 64 mph the satnav shows 60 mph
At an indicated 43 mph the satnav shows 40 mph. etc.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest3521 on December 14, 2014, 05:54:19 PM
As a retired truck driver, I can verify that Tachographs fitted to trucks are very accurate and they always agreed with my GPS.
When the same GPS unit is used in my jazz it always give a different reading to the Jazz speedo.
At an indicated 64 mph the satnav shows 64 mph
At an indicated 43 mph the satnav shows 40 mph. etc.

Interesting, I'm going to try another GPS to cross check my findings.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: culzean on December 14, 2014, 06:24:17 PM
GPS speed should in theory be the most accurate,  speedometers in vehicles are normally designed to read up to 10% or more 'fast' for obvious reasons,  but cannot read less than the vehicles speed (again for obvious reasons).

http://gpssystems.net/accurate-gpsbased-speedometer/ (http://gpssystems.net/accurate-gpsbased-speedometer/)


the speed of revolution of the wheel will be based on the radius between axle and ground,  this depends on tyre size, tyre wear (about 2% between a new and illegal worn tyre),  how hard the tyre is inflated (which is how the tyre deflation works on a Jazz by counting differing rates of ABS pulses* between wheels, the deflating tyre will have a smaller rolling radius and appear to be going faster than the other wheels. (*not brand new Jazz because they now have pressure sensors in valves).
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: applicationcen on December 15, 2014, 01:19:33 PM
My CoPilot sat nav (in my iPhone) and the Road Angel report the same speeds within a very close margin.

Both of them indicate that every car I have used them in is going a few miles slower than the speedomoter of the vehicle says the car is going.

The car speedo reads 70, speed as reported by sat nav and Road Angel 67mph.
50 relates to 48 mph roughly.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest3521 on December 15, 2014, 07:06:19 PM
GPS speed should in theory be the most accurate,  speedometers in vehicles are normally designed to read up to 10% or more 'fast' for obvious reasons,  but cannot read less than the vehicles speed (again for obvious reasons).
http://gpssystems.net/accurate-gpsbased-speedometer/ (http://gpssystems.net/accurate-gpsbased-speedometer/)
the speed of revolution of the wheel will be based on the radius between axle and ground,  this depends on tyre size, tyre wear (about 2% between a new and illegal worn tyre),  how hard the tyre is inflated (which is how the tyre deflation works on a Jazz by counting differing rates of ABS pulses* between wheels, the deflating tyre will have a smaller rolling radius and appear to be going faster than the other wheels. (*not brand new Jazz because they now have pressure sensors in valves).

I use a GPS speedometer in my classic cars as they aren't as accurate/linear or stable as modern electronic ones.
What erks me is that the OBD MPH reading is spot on (+/-1digit) and that signal is what is coming from the wheel sensors >:(.
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: degzi on December 25, 2014, 08:39:26 PM
If your in the game for decent winter tyres try http://www.nordiccartyres.com (http://www.nordiccartyres.com)

Highly rated winter tyre.  ;)
Title: Re: Winter wheel & tyre sizes for 2010 Jazz 1.4 Si
Post by: guest3521 on December 30, 2014, 07:24:50 AM
Interesting, I'm going to try another GPS to cross check my findings.

I've tried another GPS and it was within 1mph, which is acceptable, not tried the sat navs yet, so I'll give then a try and see what readings they give 8).