34/17/16 Goodyears

I'm going to order a new set of Goodyears for my altered to replace M/T's. I've tried everything to make them them work but with no luck.
I've had trouble with the M/T's with tire shake and spinning. What compound should I run? 1490's?
125" wb Altered/TAFC chassis
2165lbs with driver
470ci Blown alky BBC/14-71
Coan XST superglide
Coan Bolt together converter
4.30 gear
16" beadlocks
I have ran a 6.88@199 with the M/T's shaking and spinning

 

Tire Shake & Spin

Mac - this is the 3rd time that I have copied and pasted this response on ITA....but it's worth saying again....might help your tire problem....maybe borrow an old set of Goodyears or Hoosers to try before calling it a tire problem...but give this gear ratio idea some consideration...
There are a lot of other variables....but here is my experience....Lencodrive automatic with 1.38 & 1.31 for a 1.80 low in the trans and a 3.89 in the rear - overall 1st gear was a 7.03....worked on most tracks...but was on the edge of getting loose and shaking. I bought new chassis in 2006 with a Top Loader and a 4.29 rear gear - transplanted the drivetrain from old car. Shook hard or spun every lap! The overall 1st gear was now a 7.75....just too much leverage! So we engaged the 2-3 unit (Frank Parks suggestion) and now run as a 1.38 X 4.29 (2 speed) and the overall 1st gear = 5.92...smooth as silk....60 foot is 9.60-1.00 range and we can run it down a dirt road....I know the clutch guys may have totally different ideas on gear ratio...but with a converter keeping the 1st gear ratio under 6:1 seems to be easier to get down most tracks...but we are mostly match racing and don't run national event tracks very often...hope this helps...

 

I'm still thinking of changing to a 4.10 rear gear to get it the ratio(7.74 to 7.38) down a bit. The M/T's need to be replaced now so I thought I would put some Goodyears on?

 

hey mac... i own a fuel altered running a mike's monster glide. i have run it on both alcohol and nitro (90%). with our alcohol set up we ran a 3.89 rear gear. i am currently the driver for the nitro madness car mentioned above and it's got 3.89 in it as well. i would say drop down to a 3.90 or less (numerically) in the rear end... you'll be glad you did.

 

I don't wanna keep harping on this subject....I friend in St. Loius area is having the same problem...Powerglide with 1.80 low and he changed from a 3.89 to a 4.10....jumped all over the place at the hit. Back to the 3.89 and he tried a 36" tall tire and it behaved better, but still not real drivable off the line. He kept talking about loosing MPH on the big end by the gear ratio/tire combo...but my argument was "who cares about the MPH if he can't past the 60' mark under power" - LOL.

If there were a few more P/G ratios available for these cars, it would make it much easier to solve. A 3.70 rear would help also - 1.80 X 3.70 = 6.66, but top end performance would be compromised as my St. Louis friend is worried about.....it's your call, but less gear sure solves the drivability problem....Scott Gaulter 515-987-4900 if you want to discuss in more detail tonight...

 

our car works great with hoosiers and beadlocks. 33.5x17x16 co6 compound. we never got good years to work on our deal.....violent tire shake. changed everything we could to try to work around it, and couldn't fix it. put the hoosiers on and haven't looked back. there is definately a way to make anything work, on any car.........but there is definately a reason that most of the blown alky cars run hoosiers ......they work. my 2 cents for you would be to try the hoosiers and drop back on the rear gear a little. i think you can make a 4.10 work in there.talk to a few people who run a similar car to yours before you make your decision. let us know how things turn out.

 

timing

You didn't mention a timing control but if you don't have one it will probably do a lot more than tires. We run a roots/wedge/glide promod car and have good luck dumping timing on the hit to control shake.
I've seen a few hemi door cars do ok with full timing but not a wedge. After all the money we spent fighting it i'd NEVER run a blown convertor deal without a msd 8973 minimum.
Our car would be a turtle if we geared it until it quit shaking.
Mike