[arkwoo]

Hi all,

I'm doing research on tires for the back of my Pro Street Camaro.

This is a tubbed / back-half / ladder-bar car making pretty good power and gobs of torque - BBC 427 / 671 Blower / 2 x 750 cfm 4150 HP carbs / TCI Comp TH400 / Trans brake / 4.10 gears / Detroit Locker / 33 spline Mosers / MSD Digital 6 Plus two-step box. The drive train is pretty stout at this point and I'm almost ready for the track.

My rear tires are the last item to sort out. My problem is footprint, tire diameter and clearance. The rear fender wells have been tubbed, as stated, but they've not been lipped or stretched. As a result, things are a little tight between the tires and the lower fender sheetmetal. Here’s a view of the ride tho there isn’t really a good view of the rear tire clearance areas.

www.racingjunkrides.com/view_ride/1818/

I’m running 15 inch tall / 14 inch wide ProStars wheels with Mickey Thompson 31 x 18.50 Sportsmans on the back with lots of clearance inside the tubs. The problem is the bottom rear fender lips where the sheetmetal rolls back under the body. These tires do fit though its pretty tight.

Long story made short - I purchased and mounted a set of new MT 31 x 18.50 Sportsman Pros (I need something I can run on the street and still hook with on the track) and immediately ran into problems. The new MT Pros are a *lot* taller than their same size non-Pro cousins and will not fit inside my fenders. Both old and new tires are advertised as 31 x 18.50 but the Pro's diameter is substantially bigger. I talked to the folks at Mickey Thomspon and was told that there should be one quarter to one half inch difference in tire diameter between the two sets of tires. I'm actually seeing closer to an inch and a half difference.

Anybody else have this experience with MT Sportsman Pros ?

I can drop back to MT 29 x 18.50 Pro's but then my gearing will change, etc. What suggestions can you give for street legal race tires in this size range ? I want to stick with the 18.50 wide, approx 30 inch diameter DOT street slicks. Again, I’m going to need all the hook I can get with this blower motor and approx 3600 lb car.

The obvious solution will be to stretch the fender wells in the rear, but Mama tells me I've used up my big toy budget for this year (and probably next).

Any suggestions ?

Harry

[496pickup]

We have about the same setup as yours but in a 69 with a 4-link. We needed to cut the back of the fender just in back of the tire to get those big tires to fit. We have not yet cleaned it up and it still looks terrible. Also, we have not yet driven the car so I cant tell if it will hook up with those tires or not.

[arkwoo]

Thanks for the response, 496pickup.

I've been considering the same thing - this is a ladder bar car so like you it'd mean trimming the rear fender lip and moving the rear-end back at least an inch and a half - If this is the route I go, I'll have to gimmick up an extension to the forward ladder bar mounts since I don't have that much adjustment available in my ladder bar heim joints.

I'm thinking that for the time being, I'll end up running the 29 x 18.50 tires for now. I don't want to do that, but I also don't want to tie this ride up for another 6 months while I save my pennies to get it into a body shop.

What motor, trans and gears are you running in your 69 ?

Harry

[pasadenahotrod]

So the kids who dwell here understand, there is no such thing as a street-legal drag slick.

[arkwoo]

Originally Posted by pasadenahotrod

So the kids who dwell here understand, there is no such thing as a street-legal drag slick.

Just to be clear - Hoosier Quicktime Pro's are essentially slicks, with siping (minimal tread grooves) to make them DOT compliant. That is what I meant. The term 'slicks' also imply softer D-compound tires. Help me come up with a better term and I'll use that instead of 'street legal slicks'. My intent was not to legitimize the use of true racing slicks on the street.

What else were you trying to clear up ?

[Flipper_1938]

Originally Posted by arkwoo

Just to be clear - Hoosier Quicktime Pro's are essentially slicks, with siping (minimal tread grooves) to make them DOT compliant. That is what I meant. The term 'slicks' also imply softer D-compound tires. Help me come up with a better term and I'll use that instead of 'street legal slicks'. My intent was not to legitimize the use of true racing slicks on the street.

What else were you trying to clear up ?

I'd bet that damn near everybody else understood what you meant.

[TurboS10]

I have 33x18.5 ET streets on my S-10. You might check into a 31 and see if it is more closely matched to the ET's.

[arkwoo]

Originally Posted by TurboS10

I have 33x18.5 ET streets on my S-10. You might check into a 31 and see if it is more closely matched to the ET's.

Holy smokes ! I just checked out your photo album, that is one healthy S-10 !!!

I think I've located a set of M&H tires that'll work for now, they're MSS-010 RaceMasters. Check out the thumbnail below.

Tire Overall Diameter: 30.0''
Average Roll Out/
Circumference: 94.0''
Tire Tread Width: 14.5''
Tire Section Width: 18.0''
Wheel Diameter: 15''
Required
Wheel Width: 14''

My current rollout with the standard 31 x 18.50 Sportsmans is about 97". the rollout for the new 31 x 18.50 Sportsman Pro's I just bought is about 100.5", over 3 inches longer in rollout. That's enough of a diameter increase that the new ones don't fit. My hope with the RaceMasters is that they'll be just about right with tire growth at speed so as to not cause problems with clearance.

Sometime next year I'll go about finding a local shop here I can get to extend my wheelwell openings a few inches. That'll take care of the problem and let me go back to the taller tires.

[TurboS10]

Glad you found some tires. The ET streets are not worth anything on the street since they are truely a slick with grooves. Those you found will probably be better all around.

My S-10 is healthy when it is running. It has been down for a while now due to my other projects taking my time and interest right now. I just need to get a set of gaskets and put the heads back on, but I have not had time. It is fun when you push the go pedal

[arkwoo]

Just finished a discussion with M&H. Because of low demand, they are not currently manufacturing the MSS-010 tire. Lucky me.

I did discover that they have some number of these tires in back inventory but was told that these are probably somewhat dated and I should be wary of picking them up.

So, I'm now back where I started. I may have to fall back to the 29 x 18.50 Sportsman Pro tires until I can get my wheelwells stretched.

Dang.

[arkwoo]

Ok, I finally settled on using 29 x 18.50 Sportsman Pro's. They're certainly shorter than the 31's I have been using but I now have clearance for tire growth, etc.

I ran around for the first time today with the new rubber on and am satisfied with the result. These things really hook well - I did a little warm up down at the local tire shop parking lot and these tires want to hook pretty well once you get them hot.

And, I now have wrinkles in my sidewalls



I'm a pretty happy guy. Now I need to run the bead lock screws in and move on to the next challange prior to hitting the track