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Tire Size
- Thread starter Saff
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Geo Hahn
Yoda
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Here's a page that might help...
https://www.yokohamatire.com/utsizesys.asp
Per this, the original aspect ratio would have been 82.
Perhaps your question is: What tires would others recommend? To get a good answer you may want to indicate what type of driving you plan on doing and whether originality, performance or cost is most important.
https://www.yokohamatire.com/utsizesys.asp
Per this, the original aspect ratio would have been 82.
Perhaps your question is: What tires would others recommend? To get a good answer you may want to indicate what type of driving you plan on doing and whether originality, performance or cost is most important.
OP
Saff
Member
Offline
Hi, George -
Thanks for the link. It looks like the profile is 82 by omission - unspecified.
My biggest requirement for tire sizing is avoiding rear wheel rub on my GT6, so I won't be changing the size intentionally. That said, I would favor a more sticky compound - any suggestions in that area would be most welcome.
Thanks.
Thanks for the link. It looks like the profile is 82 by omission - unspecified.
My biggest requirement for tire sizing is avoiding rear wheel rub on my GT6, so I won't be changing the size intentionally. That said, I would favor a more sticky compound - any suggestions in that area would be most welcome.
Thanks.
Saff, the tire sizes specified in my GT6 shop manual are:
155-13
155SR-13
5.60S-13
5.60S-13X
Mine is getting 185/70R/13's on it. I ran BFG Touring TA's on another car that gripped well, and I've heard good things about Sumitomo's on LBC's. I'm going to try the Sumo's on the Midget.
Jeff
155-13
155SR-13
5.60S-13
5.60S-13X
Mine is getting 185/70R/13's on it. I ran BFG Touring TA's on another car that gripped well, and I've heard good things about Sumitomo's on LBC's. I'm going to try the Sumo's on the Midget.
Jeff
V
vagt6
Guest
Guest
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The 185 70R 13s may rub a little bit on the lip of the fender wells. Rubbing depends on your suspension condition (excess travel will allow more rubbing) and how it is set up.
My tires rub a little on the fender wells, but only under very hard cornering. I don't often drive that agressively, so it's not a great matter of concern for me.
If your suspension is in good condition and you add 185 70 series tires, you might have some contact with the fender. Some folks (certainly not ME!) gently roll the lip of the fender wells up (and then wire brush, prime and paint them) and away from the tires. This curtails rubbing, but may not stop it completely.
EVeryone's GT6 suspension is different, it may not be an issue with your car.
Good luck, let us know how it goes!
My tires rub a little on the fender wells, but only under very hard cornering. I don't often drive that agressively, so it's not a great matter of concern for me.
If your suspension is in good condition and you add 185 70 series tires, you might have some contact with the fender. Some folks (certainly not ME!) gently roll the lip of the fender wells up (and then wire brush, prime and paint them) and away from the tires. This curtails rubbing, but may not stop it completely.
EVeryone's GT6 suspension is different, it may not be an issue with your car.
Good luck, let us know how it goes!
OP
Saff
Member
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Do you put the 185/70's on stock rims? There's over an inch difference in tread width between 155 and 185. Does the sidewall simply make up the difference?
Mt calculations show only 0.1" difference in outer diameter but it's the extra inch of width that I'm worried about. It's possible that my small-town tire dealer will let me swap them out if they rub. I'll have to check.
Thanks to all for the replies.
Mt calculations show only 0.1" difference in outer diameter but it's the extra inch of width that I'm worried about. It's possible that my small-town tire dealer will let me swap them out if they rub. I'll have to check.
Thanks to all for the replies.
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If you're staying with the original 4.5" wheel, I'd go with a 175/70R13. It's approximately the same diameter as a 155 but with a slightly wider tread. Of course, it's getting difficult to find anything approaching a "performance" radial in this or any other 13" size nowadays, but 175/70 is about the widest that can safety fit on the 4.5" rim. This size always worked well for me.
OP
Saff
Member
Offline
Hi, Andy and welcome! I used to see lots of your posts on the autox boards. Between you and Randall, a wealth of knowledge got passed around.
I did end up going with 175/70R13 tires. My calculation was off somewhere - the 185's were about half and inch taller and over an inch wider. They definitely would have rubbed.
And what a difference the new rubber makes!! I got a set of Dunlops in a fairly soft compound. I thought I had some minor issues to clear up before my upcoming road trip (heading up almost to your place) but the new tires addressed them all. Don't know if you have Sam's Clubs yet on "The G'island" but I was out the door for $180.
Good to see your name and I had to chuckle at the "newbie" rank!
I did end up going with 175/70R13 tires. My calculation was off somewhere - the 185's were about half and inch taller and over an inch wider. They definitely would have rubbed.
And what a difference the new rubber makes!! I got a set of Dunlops in a fairly soft compound. I thought I had some minor issues to clear up before my upcoming road trip (heading up almost to your place) but the new tires addressed them all. Don't know if you have Sam's Clubs yet on "The G'island" but I was out the door for $180.
Good to see your name and I had to chuckle at the "newbie" rank!
Trevor Triumph
Jedi Knight
Offline
The Spitfire GT6 Magazine has a a page on their web site regarding tire sizes for Spitfires and GT6s. That might be helpful. <www.triumphspitfire.com>
T.T.
T.T.
Offline
OK, now I'm curious. Which Dunlops did you get?
Broke my heart years ago when I picked up a very nice used set of genuine Mini-Lite wheels for my GT6+. Two were "bare" and the other two had mounted 185/70 R 13 Pirellis. Tried them on the 6+ and they wouldn't fit. Due to the rear shock mount design on the "rotoflex" rear end, the wheel itself rubbed on the shock. I saw no need to ruin either a Koni or a Mini-Lite wheel, so they went into the garage, and I stayed with the stock steel wheels. :-(
Oh, and 1. I'm still on many of the Team.Net lists; and 2. despite the name of my township, I'm actually well north of NYC and Long Island. Many people confuse Nassau County Long Island with the town of Nassau and village of East Nassau (where I live), in Rensselaer County, near Albany!
Broke my heart years ago when I picked up a very nice used set of genuine Mini-Lite wheels for my GT6+. Two were "bare" and the other two had mounted 185/70 R 13 Pirellis. Tried them on the 6+ and they wouldn't fit. Due to the rear shock mount design on the "rotoflex" rear end, the wheel itself rubbed on the shock. I saw no need to ruin either a Koni or a Mini-Lite wheel, so they went into the garage, and I stayed with the stock steel wheels. :-(
Oh, and 1. I'm still on many of the Team.Net lists; and 2. despite the name of my township, I'm actually well north of NYC and Long Island. Many people confuse Nassau County Long Island with the town of Nassau and village of East Nassau (where I live), in Rensselaer County, near Albany!
Bob Buxbaum
Jedi Hopeful
Offline
You did not (I believe) indicate what wheel size you have. I have Panasport 13 x 5.5 wheels with 185x70/13 BFGs that I bought at Sam's Club for next to nothing. No rubbing problems. Go to www.tirerack.com for all sorts of choices for "sticky" tires. Keep in mind that rim width means everything when it's time to buy new tires.
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General note on tire hardness:
One of the most neglected tire measurements on performance tires is the durometer (tire compound hardness). This is measured on the "Shore A Scale" with what else, a tire durometer. This is an indenspensible tool for anyone who is into tire performance.
https://www.longacreracing.com/catalog/item.asp?id=236&catid=9
Tires compounded for long life may measure 85 to 90 on this scale. Tires made for high traction but shorter life may measure 40 on the same scale. Since all tires harden with age & temperature (the rubber never really stops curing) there can be up to 20 points difference between a "new" new tire & the same new tire that has been stored in high heat for several years. Obviously the harder tire will have less friction.
Anyone who has a serious interest in tire grip will benefit from the $60 investment in a tire durometer. At the least, it can help you use some science with your tire selection. Probably a good starting point would be a tire with an off the shelf reading of no more than 60 Shore A. As the tires harden with heat & time the numbers will just go up.
Sometimes, you will find a cheaper tire with a lower rated mileage to have more grip & lower Shore A reading, than a more expensive tire.
D
One of the most neglected tire measurements on performance tires is the durometer (tire compound hardness). This is measured on the "Shore A Scale" with what else, a tire durometer. This is an indenspensible tool for anyone who is into tire performance.
https://www.longacreracing.com/catalog/item.asp?id=236&catid=9
Tires compounded for long life may measure 85 to 90 on this scale. Tires made for high traction but shorter life may measure 40 on the same scale. Since all tires harden with age & temperature (the rubber never really stops curing) there can be up to 20 points difference between a "new" new tire & the same new tire that has been stored in high heat for several years. Obviously the harder tire will have less friction.
Anyone who has a serious interest in tire grip will benefit from the $60 investment in a tire durometer. At the least, it can help you use some science with your tire selection. Probably a good starting point would be a tire with an off the shelf reading of no more than 60 Shore A. As the tires harden with heat & time the numbers will just go up.
Sometimes, you will find a cheaper tire with a lower rated mileage to have more grip & lower Shore A reading, than a more expensive tire.
D