I've got Avon CR66ZZ on my CAV at present and the fronts need replacement. I have some part worn Yoko A032r (225/60/15), can I try these at the front. I am attending a track day later this week and am unsure of the effect of this tyre combo on the balance of the car. What do you guys think of mixing tyres?.
tyre mixing
- Thread starter cavgt40
- Start date
Howard Jones
Supporter
First, The tires must be safe to use on track. Not old, found them in the barn, tires. Good tread, no patches, no sidewall cracks, no flatspots, and not too old. More than a year or so the sun outside and you might as well thrown them out. Same with standing in the corner of the garage getting hard for years. They are no good and are a waste of time and money mounting them. Have a look inside the tires. If anything looks wrong, deformed belts, cracks, then throw them out. One good curbing can ruin a tire and you can't see it from the outside. Put on a good ballance job.
Second, some basic comparison to the other tires on the car. I wouldn't run a set of dot slicks with a summer only street tire. If I had a front set of high performance Z rated summer tires and wanted to use them with another brand of the same basic types on the rear then I would.
Never use different brands on the same end of the car. NEVER!
Third, can you balance your car at the track? Are the roll bars adjustable? At least the rear? Try to setup the car with a little understeer at first and work back to neutral.
If you have a set of safe, newish tires then use them. Be ready to work on setup a little more than usual. Beware of getting yourself into a big oversteer setup and running hard right out off the trailer.
Use the day as a 80% fun day at the track, at least in the morning. Check tire pressures after every session and compair to previous data. This could turn into a good data collection session.
Maybe run in a slower group than normal for the first session and see how you go. Drive it to the fun limmit and enjoy. After all it's not a race.
Second, some basic comparison to the other tires on the car. I wouldn't run a set of dot slicks with a summer only street tire. If I had a front set of high performance Z rated summer tires and wanted to use them with another brand of the same basic types on the rear then I would.
Never use different brands on the same end of the car. NEVER!
Third, can you balance your car at the track? Are the roll bars adjustable? At least the rear? Try to setup the car with a little understeer at first and work back to neutral.
If you have a set of safe, newish tires then use them. Be ready to work on setup a little more than usual. Beware of getting yourself into a big oversteer setup and running hard right out off the trailer.
Use the day as a 80% fun day at the track, at least in the morning. Check tire pressures after every session and compair to previous data. This could turn into a good data collection session.
Maybe run in a slower group than normal for the first session and see how you go. Drive it to the fun limmit and enjoy. After all it's not a race.
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Thanks for the comments and advice guys. The yoko A032r tyre is a track day/race tyre like the Avon CR66zz and both are soft compounds. So I am hoping that they have similar dry grip levels and the combo will not significantly alter the balance of the car. However I will play safe and set the car up with a little understeer initially.
I would defenitely give it a try. You never now what you will find out.
Í had a race weekend with my bike 2 years ago. On sunday morning my rear DUNLOP KR 164 was pretty good used and i wanted to safe it for the afternoon race. I use to have a second set of rims with me just in case. They are shoed with a complete different tire. The KR´s ( KR 825 front and KR 164 rear ) are soft compound vintage race tires, which actualy are run be every serious contender in my class, but they are a old construction concept. The front tire is pretty small in witdh and section height (2,75/3,75 -18) so overall diameter is very close to a modern 120/70/17 tire. THe rear. KR 164 is a 3,75/5,00-18 size on a 2,75" rim, so not the biggest tire also.
Beeing the lazy guy i´m, i did not want to change the complete set and left the front tire in and just replaced the rear with a modern Bridgestone BT012 tire in a big fat 160/60/18 Size on a 4" rim.
Everyone told me that i´m crazy , but i gave it a try and came back into the pits after the first session with a big big smile. THe bike was completely changed to the positiv. much more response in steering in, no underster at all anymore. I could carry much more speed into the turns and could accelerate earlier.
Make a long story short, i left this combo in for the race and won.
I modified this set up a little with a even more grippy BT090 in 150/60/18 on the rear, but the front is still the tiny KR 825. Happy with that combo since then.
If you don´t try you won´t know and if you are a decent driver and have a feeling for your car, your will feel if it works better or if it is better to go slow before you are in the critical area.
Usualy GT40´s are running a 215/60/15 in front when they are equipped with thhe CR6zz. This tire has only a contact witdh of 185 mm. So your 225 Yoko is probably a real 225 and will give you much more contact patch in front, which gives you probably more grip on the front ( if the compounds are similar). If the car was balanced before the car could be more prone to oversteer and you may end up to soften your rear swaybar to give it more grip at that end as well and achieving more corner speed over all. Just my theory for what it´s worth.
TOM
Í had a race weekend with my bike 2 years ago. On sunday morning my rear DUNLOP KR 164 was pretty good used and i wanted to safe it for the afternoon race. I use to have a second set of rims with me just in case. They are shoed with a complete different tire. The KR´s ( KR 825 front and KR 164 rear ) are soft compound vintage race tires, which actualy are run be every serious contender in my class, but they are a old construction concept. The front tire is pretty small in witdh and section height (2,75/3,75 -18) so overall diameter is very close to a modern 120/70/17 tire. THe rear. KR 164 is a 3,75/5,00-18 size on a 2,75" rim, so not the biggest tire also.
Beeing the lazy guy i´m, i did not want to change the complete set and left the front tire in and just replaced the rear with a modern Bridgestone BT012 tire in a big fat 160/60/18 Size on a 4" rim.
Everyone told me that i´m crazy , but i gave it a try and came back into the pits after the first session with a big big smile. THe bike was completely changed to the positiv. much more response in steering in, no underster at all anymore. I could carry much more speed into the turns and could accelerate earlier.
Make a long story short, i left this combo in for the race and won.
I modified this set up a little with a even more grippy BT090 in 150/60/18 on the rear, but the front is still the tiny KR 825. Happy with that combo since then.
If you don´t try you won´t know and if you are a decent driver and have a feeling for your car, your will feel if it works better or if it is better to go slow before you are in the critical area.
Usualy GT40´s are running a 215/60/15 in front when they are equipped with thhe CR6zz. This tire has only a contact witdh of 185 mm. So your 225 Yoko is probably a real 225 and will give you much more contact patch in front, which gives you probably more grip on the front ( if the compounds are similar). If the car was balanced before the car could be more prone to oversteer and you may end up to soften your rear swaybar to give it more grip at that end as well and achieving more corner speed over all. Just my theory for what it´s worth.
TOM
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