What Tyres Are You Using?

[emphasis303]

Hello everyone

I would like to know what tyres you are using and if your happy with them.

Im soon to be needing new tyres so wanted to get your opinions.

Also, I currently have 195 55 16 on the car and wanted to upgrade them to 215 60 16 for a cushier ride and possibly better handling, does anyone know whether Ill have any problems with this size (apart from mpg decrease) i.e clearance tramlining.

Thank you very much

[cootuk]

Dealer put four Bridgestone Turanza ER30s on mine - would be 90 quid a corner locally.

http://priuschat.com/forums/gen-ii-prius-m...05-50-16-a.html

Looks like 205/55/16 gives a really wide choice of tyres a lot cheaper depending if you want to keep low rolling resistance or not.

[emphasis303]

Hmm im not to fussed about low rolling resistance as ive read and been told it only makes a 5% diff and would be happy to sacrifice that for a better overall ride, but am unsure if the size would be a problem. Also im not sure if there will be much difference in handling between 205 and 215 and whether if would be better to put 205 65 than 215 60

[Sagitar]

Continental Winter contact TS 830 195/65 R15 91T, for the winter.

Then back to Michelin Pilot Primacy 215/45 R17 87W, for the summer.

The Michelins seemed fne to me. I was particularly pleased with the way they handled very wet conditions on motorways.

The Contis have been brilliant on the snow and ice in the recent past.

[emphasis303]

are you using oem rims for both sets?

[Chris Dance]

My car has original Bridgestones but lots of members on this site changed to Michelin and say they are good. If you do change tyres do not forget to do a tyre reset as per owners manual. I would change mine to Michelin but my Bridgestones have very litle wear. Check out earlier threads on this matter on this forum.

[Sagitar]

are you using oem rims for both sets?

No. The winter tyres are on Dezent Type A 15x6.5 alloys.

I enquired of Toyota but they wanted about £1,100 for a set of four 15" OEM wheels with those funny plastics covers - has to be a bit of a joke . . . . .

[Sagitar]

are you using oem rims for both sets?

No. The winter tyres are on Dezent Type A 15x6.5 alloys.

I enquired of Toyota but they wanted about £1,100 for a set of four 15" OEM wheels with those funny plastics covers - has to be a bit of a joke . . . . .

I washed the car this morning to get rid of all the salt I picked up over Christmas and then took some pics of a wheel/tyre so you can see what they look like.

The final pic is of one of the Michelins so that you can see how different the tread formation is.

[emphasis303]

wow thanks a lot for the pics, yeh I can see the difference between the two, do you notice a drop in mpg when moving to the winter tyres? or have you purposely dropped the size to compensate for the increase in rolling resistance? Also do you enjoy not feeling as much of the road with the higher profile tyres? or is there not much difference?

btw cheers chris, I never even knew there was a tyre reset option

Thanks very much everyone

[Sagitar]

wow thanks a lot for the pics, yeh I can see the difference between the two, do you notice a drop in mpg when moving to the winter tyres?

There hasn't really been enough time to tell. My mileage was dropping anyway as it got colder and given the kind of difficult conditions in which we have been driving, some reduction was to be expected. The last fill is showing something over 53 m.p.g. at present so I'll not complain about that.

have you purposely dropped the size to compensate for the increase in rolling resistance?

The choices were much simpler than that. Winter tyres are only available in a limited range of sizes. It seemed sensible to put on a hgher profile tyre given the increased incidence of potholes etc in the winter and the reduced chance of kerbing the alloys. My first thought was to go with a standard Toyota size and all that together said 15" with 195/65. The external diameter of the tyre is almost precisely the same as the 17" Michelins.

Also do you enjoy not feeling as much of the road with the higher profile tyres? or is there not much difference?

I haven't really noticed much difference, but again I have to say that the driving conditions recently haven't allowed very enthusiastic driving. I would think that the softer elastomer and the more flexible tread pattern will probably make more difference than the change in tyre wall height. The tyres are also inflated a bit harder so that should compensate somewhat for the reduction in wall stiffness.

[emphasis303]

Thank you very much for your help, I was considering having a set of winter tyres but as we dont see too much snow down here and with most roads gritted im inclined towards a set of good all weather tyres that will handle best in wet weather. Ive seen that apparently tyres with v grooves are best for this?

Ive read that the goodyear hydrgrip is best for this so am considering these.

Thank you

[emphasis303]

Ok after reading a bit I realise my previous post was slightly ignorant, as once non winter tyres pass about 7 Celsius they begin to stiffen which in effect causes a lack of grip. So i think I too will purchase a winter set and then sort out the summer tyres on the oem set sometime in april depending on weather of course

[Sagitar]

Ok after reading a bit I realise my previous post was slightly ignorant, as once non winter tyres pass about 7 Celsius they begin to stiffen which in effect causes a lack of grip. So i think I too will purchase a winter set and then sort out the summer tyres on the oem set sometime in april depending on weather of course

A very small percentage of people in the UK fit winter tyres and I guess one of the reasons is the general assumption that they are only for use on snow and ice and we don't get snow and ice often enough to make it worthwhile. But as you rightly say, they do give better performance, even on dry roads, when the temperature falls below about 7 degrees C. Following from that, I think that most people, especially those not using rear-wheel-drive, manage pretty well on summer tyres for most of the time, especially with the increasing use of ABS, traction control and vehicle stability control.

From my experience, adding a set of winter wheels and tyres put about £600 onto the capital cost of the vehicle. It may be possible to find used wheels and lower that cost somewhat. The other problem for many people will be to find somewhere to store an extra set of wheels/tyres.

In terms of running costs, an extra set of tyres seems to me to be a neutral factor in the longer term i.e. wear is spread over eight tyres instead of four so they will last much longer.

In my case, the cost was not a significant issue and I have no problem with storage. Keeping mobile throughout the winter is important to me and so I judged it was all worthwhile. I am sure that others will make entirely different judgements.

[emphasis303]

Ive been reading and on the phone all day trying to find the biggest tyre I can fit on 16" rims, I spoke to a main dealer and the mechanic said 205 60 16 should be fine but to try one wheel first, I cant seem to find a definitive answer from anyone as they all say it should fit. I decided I will fit the winter tyres now and sort out a set of summer tyres when the weather picks up, that way I dont need to fork out on new alloys just yet :)

[cootuk]

Does the GenII have the tyre rest function as I can't see anything in the manual?

[emphasis303]

I was looking as well, I read its only available for the models with satnav, as you change it via the sat nav service menu, which unfortunately I thought was an expense not worthy of the money due to the limitations of the software. I guess Ill just have to drive 5mph slower with the bigger tyres :)

Another thing I meant to ask was, someone in a tyre shop mentioned that if you change the tyre size it messes up the gear ratios or something.

Anyone heard of this?

[Sagitar]

I was looking as well, I read its only available for the models with satnav, as you change it via the sat nav service menu, which unfortunately I thought was an expense not worthy of the money due to the limitations of the software. I guess Ill just have to drive 5mph slower with the bigger tyres :)

Another thing I meant to ask was, someone in a tyre shop mentioned that if you change the tyre size it messes up the gear ratios or something.

Anyone heard of this?

There is no way that the gear ratios are affected by changing tyres, however the distance that the car travels for each engine revolution is a function of both the gear ratios and the external diameter of the wheels/tyres. So, if you increase the size of the wheel/tyre external diameter, the distance travelled for each engine revolution will increase and vice versa. The signal that is input to the speedo is generally taken from the output side of the gearbox so anything that is changed between the gearbox and the road makes a difference to the real speed, without making a similar change to the speedo indication. Vehicles with a tyre size reset function, enable a change in the speedo input signal to match physical changes downstream of the gearbox.

If you change tyre width or wheel size, you need to change the tyre profile to maintain the same external diameter. There are tables and calculators that show the differences of tyre circumference that result from fitting different tyres but if you look for proper equivalence, the differences are small (often within the limits of the wear tolerance) and make little practical difference. You should be able to find a table or calculator by Googling.

The real distance travelled in a single revolution of a tyre is not exactly equal to the circumference of the tyre, because the tyre flexes as it rolls and the distance from the axle centre to the road surface is smaller than the diameter of the unloaded tyre. Tyre wear reduces the tyre diameter over time and inflation pressure and tyre wall stiffness will affect the situation and so it is difficult to be precise about it. This is why speedos are always calibrated to show a higher figure than the actual.

The theoretical difference in rolling distance between my 15" 195/65 and my 17" 215/45 is about 1.4%

Wearing 6mm off my 215/45 17" tyres would make a difference of about 1.9%

So I am not going to worry too much about it . . . . . :)

[Chris Dance]

Tyre change calibration. Go to Prius Navigation System Owners Manual. Go to page 111, the tyre calibration is there with associated diagram. You need to do this if you change tyres.

Chris.

[Sagitar]

Tyre change calibration. Go to Prius Navigation System Owners Manual. Go to page 111, the tyre calibration is there with associated diagram. You need to do this if you change tyres.

Chris.

Thanks Chris. The information is on page 301 of my manual (Gen III T-Spirit) and is concerned only with the navigation system as far as I can see. It asks for no information about actual tyre size and I therefore assumed when I read it that it was there to take account of wear when changing worn for new tyres of the same nominal size. I had further assumed that the navigation system must have the capability to "learn" about the physical characteristics of the vehicle by comparing calculated positions with "real" positions plotted by the GPS and that the calibration was simply nullifying the learned data and starting again with the new tyres.

There are warnings about possible inaccuracies in the navigation system arising from various things including tyre sizes on page 358 but again they appear to be related only to the navigation system.

In some vehicles (e.g. the Lexus that I drove before the Prius) there is provision for speedo calibration to take account of the use of wheels of significant difference in size. I have been unable to find any reference to such a system in the GenIII Prius. Do you know of any?

[Chris Dance]

Hi Sagitar, I am only familiar with the GEN 2 T Spirit.

Perhaps the Gen 3 is different. Sorry I cannot help you with Gen 3 information.

Chris.

[emphasis303]

I was looking as well, I read its only available for the models with satnav, as you change it via the sat nav service menu, which unfortunately I thought was an expense not worthy of the money due to the limitations of the software. I guess Ill just have to drive 5mph slower with the bigger tyres :)

Another thing I meant to ask was, someone in a tyre shop mentioned that if you change the tyre size it messes up the gear ratios or something.

Anyone heard of this?

There is no way that the gear ratios are affected by changing tyres, however the distance that the car travels for each engine revolution is a function of both the gear ratios and the external diameter of the wheels/tyres. So, if you increase the size of the wheel/tyre external diameter, the distance travelled for each engine revolution will increase and vice versa. The signal that is input to the speedo is generally taken from the output side of the gearbox so anything that is changed between the gearbox and the road makes a difference to the real speed, without making a similar change to the speedo indication. Vehicles with a tyre size reset function, enable a change in the speedo input signal to match physical changes downstream of the gearbox.

If you change tyre width or wheel size, you need to change the tyre profile to maintain the same external diameter. There are tables and calculators that show the differences of tyre circumference that result from fitting different tyres but if you look for proper equivalence, the differences are small (often within the limits of the wear tolerance) and make little practical difference. You should be able to find a table or calculator by Googling.

The real distance travelled in a single revolution of a tyre is not exactly equal to the circumference of the tyre, because the tyre flexes as it rolls and the distance from the axle centre to the road surface is smaller than the diameter of the unloaded tyre. Tyre wear reduces the tyre diameter over time and inflation pressure and tyre wall stiffness will affect the situation and so it is difficult to be precise about it. This is why speedos are always calibrated to show a higher figure than the actual.

The theoretical difference in rolling distance between my 15" 195/65 and my 17" 215/45 is about 1.4%

Wearing 6mm off my 215/45 17" tyres would make a difference of about 1.9%

So I am not going to worry too much about it . . . . . :)

Hmm well im going for the 205 60 16s which will give an increase of 5.1% which will be 3.5 mph extra at 70mph, I was only worried about speed cameras but as the cameras them selves have some tolerance I think over over 5% should be fine.

[Hicardo]

Hi there guys, coming back on the point made about winter tyres and a performance drop off in the summer when the average temps are over 7deg C.

On my second car, a Saab 9-3, i fitted winter tyres last winter (Kumho IZEN, which have been fantastic), and then at the recommendation of my local tyre specialist in Sussex, i left them on the car all last summer as an experiment. This is a fast car with a performance upgrade. I have to say i experienced no drop off in grip through the summer at all. I was told that i would always, all year round, have a higher grip level with the winter tyre, as the compound is softer, but the downside would be much higher wear rate, particularly on the very hottest summer days when the road gets sticky. So i didnt drive the car on many of those days. The effect has been exactly what was expected. The fronts (which do most f the work) are now half worn after approximately 5000 miles. THe rears are 10% worn only.

So in my experience there is no drop off in performance of winter tyres as the temps get hotter. My Kumho winters have a look and tread very similar to Sagitars Contis.

I woud be interested to know if there is any hard evidence for a drop off in performance of winter tyres as the temperatures warm up, or is it just an old wives tale? Perhaps maybe the latest winter tyres are more advanced in their handling of conditions across the seasons?

Interested in your thoughts.

[cootuk]

http://www.tyres-online.co.uk/techinfo/winter.asp

From these charts it looks like winter tyres increase braking distance in most cases apart from cold and wet conditions.

[Hicardo]

Thanks for that, interesting article. Braking distance was not something i thought of, so that's given me food for thought.

Would be good to know where their tests originated and how they were conducted. I will plan to put summer tyres on the Saab this spring, and then winters on both the Prius and Saab next October. Winter tyres are the way to go at this time of year even in the UK, gives you a lot of piece of mind for relatively little outlay and inconvenience imo.

Sagitar, from where did you purchase your 15" non OE wheels?

Happy New Year!

[Sagitar]

Sagitar, from where did you purchase your 15" non OE wheels?

They are Dezent Type A wheels and I bought them through a Northampton outfit called POTN. You can find them by Googling on either Dezent or POTN.

The wheels come with lug nuts; same thread size as the Toyota studs but they need a different socket spanner size - 19mm instead of 21mm, so the key in the tool kit will not fit them. If you want a locking set, order them with the wheels. They are more expensive if ordered later.

They are a personable and helpful bunch at POTN and unlike some outfits that I explored, their wheel fitting data base includes info for the Gen 3 Prius.

Their prices are good, but they twice let me down with delivery promises, so I can't give them ten out of ten.