28x10.5/4.30 gear vs. 29.5x10.5/4.56 gear
08-12-2005, 11:34 AM
#1
28x10.5/4.30 gear vs. 29.5x10.5/4.56 gear I'm torn between the 2 combos and would like some opinions/suggestions on which one to go with. Both will put me at the traps at the rpms I need to be, but there has to be some advantages and disadvantages between the 2. This is a max effort cam only setup that will later turn into a heads/cam setup. I have a little time to make up my mind as what gear I decide because its looking towards the begining of Semptember before my rear end is going to be done. So I have until then to decide what will be going in. The tires I can get anytime. Anyhow, at 7000 rpms, it will put me at 136 mph and thats with no converter slippage or tire growth, so roughly 131-133 and thats with the 28/4.30 combo. With the 29.5/4.56 combo at 7000 rpms, I'll be at 135 mph which is probably good for 130-132. Again, both will put me right where I need to be, so what do you think? Thanks.
08-12-2005, 12:39 PM
#4
I don't mind fitting it, but if its worth it over the 28/4.30 combo. From what I've read, I'll have to trim the fenders about 1 1/2 on each side, roll the top of the lip, and either beat in the inner fenders or mini-tub. It is a lot of work, but if the 29.5/4.56 combo isnt going to be any better, then I'll just stick with the 28/4.30 combo. I need a setup that's going to hold up to a 5000 stall launch off the transbrake.
09-09-2005, 06:25 PM
#6
I talked to a source of mine (reputable suspension/chassis builder) and he was saying that a 29.5" tire is just too much tire for a mid-lower 10 sec. car even with a 4.56 gear. He said I'm just not making enough power to get a 29.5" tire rolling. I dunno...I'm confused now. I still have time to decide as my rear end won't be shipping out till next friday. If anyone has any input on what tire/gear combo they recommend for my setup, please do. Thanks.
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09-10-2005, 04:08 PM
#8
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All depends on the car.
WHo is giving you advice? I cut low 1.3 60's and a lot of 1.5 60' people tried to give me advice as well.
My new setup (heads/cam) I run a 28x10.5W tire...
With a 5500 rpm 8" converter, cam only.. on a 28x10.5" tire I trapped 128mph around 6650 RPM's.
The 29.5" will hook more consistantly if its a 10.5" width, but are you sure its 10.5 and not 10"?
WHo is giving you advice? I cut low 1.3 60's and a lot of 1.5 60' people tried to give me advice as well.
My new setup (heads/cam) I run a 28x10.5W tire...
With a 5500 rpm 8" converter, cam only.. on a 28x10.5" tire I trapped 128mph around 6650 RPM's.
The 29.5" will hook more consistantly if its a 10.5" width, but are you sure its 10.5 and not 10"?
09-10-2005, 11:45 PM
#10
I wanted more opinions. I didn't want to base my decision off of one's point of view. I wanted to throw that in here and see what people thought of it. What do you think?
Magnus, you were passing through the traps at 6650 with a 4.10 and 28x10.5 tires. If I were to run the 4.30 and the 28x10.5, I think it'll put me closer to my previous setup of 4.10 and 26" slick. A 4.30 with the 28x10.5 should spin my motor 300 rpms more through the traps than yours.
Magnus, you were passing through the traps at 6650 with a 4.10 and 28x10.5 tires. If I were to run the 4.30 and the 28x10.5, I think it'll put me closer to my previous setup of 4.10 and 26" slick. A 4.30 with the 28x10.5 should spin my motor 300 rpms more through the traps than yours.
09-11-2005, 10:48 AM
#13
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my reasoning is i was able to consistantly dead hook 28x10.5's in my setup which is similar to yours into the low 1.4's.. It became a problem when I started cutting low 1.3's.
09-11-2005, 10:59 AM
#14
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I would personally run the 29.5 if you don't mind cutting. The taller sidewall will always hook better than the shorter 28.
I would have 29.5 ,but don't want to cut my car up.
The taller sidewall is the better way to go. I'm going off all my past experience on that. Just my .02 cents.
I would have 29.5 ,but don't want to cut my car up.
The taller sidewall is the better way to go. I'm going off all my past experience on that. Just my .02 cents.
09-11-2005, 11:27 AM
#15
Magnus, the best 60 ft. I've cut is a 1.46 and thats with the old setup. (see sig.) I hope to be in the lower 1.4s when the setup is done and hopefully even cut a high 1.3 when winter comes around. If I can cut low 1.4s consistently, then I'll be happy.
TOSTO RACING, according to the gear calculator, the 4.56/29.5 combo is worth just 1 mph less than the 4.30/28 combo, however, from another calculation, the 4.56 seems not enough for that big of a tire and the 4.88 would just be too much. I would need somewhere in the 4.60-4.70 range. I want to be passing through the traps around 6900-7000, just before my rev limiter (7200).
TOSTO RACING, according to the gear calculator, the 4.56/29.5 combo is worth just 1 mph less than the 4.30/28 combo, however, from another calculation, the 4.56 seems not enough for that big of a tire and the 4.88 would just be too much. I would need somewhere in the 4.60-4.70 range. I want to be passing through the traps around 6900-7000, just before my rev limiter (7200).
09-11-2005, 12:36 PM
#17
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Originally Posted by Dragaholic
Magnus, the best 60 ft. I've cut is a 1.46 and thats with the old setup. (see sig.) I hope to be in the lower 1.4s when the setup is done and hopefully even cut a high 1.3 when winter comes around. If I can cut low 1.4s consistently, then I'll be happy.
TOSTO RACING, according to the gear calculator, the 4.56/29.5 combo is worth just 1 mph less than the 4.30/28 combo, however, from another calculation, the 4.56 seems not enough for that big of a tire and the 4.88 would just be too much. I would need somewhere in the 4.60-4.70 range. I want to be passing through the traps around 6900-7000, just before my rev limiter (7200).
TOSTO RACING, according to the gear calculator, the 4.56/29.5 combo is worth just 1 mph less than the 4.30/28 combo, however, from another calculation, the 4.56 seems not enough for that big of a tire and the 4.88 would just be too much. I would need somewhere in the 4.60-4.70 range. I want to be passing through the traps around 6900-7000, just before my rev limiter (7200).
Are you calculating tire growth as well?
09-11-2005, 04:55 PM
#19
Gizmo, if I was gonna go with that size of tire, then I might as well go all out and do surgery for the car to fit 29.5x10.5. I wanna run a 10.5 as most classes run that or dont allow anything wider. It has the stock 1st gear ratio which is 2.52.
Stu'sWS6, I'm not calculating for tire growth or converter slippage, but according to the calculator, it says 135 w/the 4.56/29.5 and 136 for the 4.30/28, but realisticaly, it'll probably be 131-134 with tire growth and slippage.
PSJ, I'd like to cut low 1.4s now and high 1.3s in the winter. If I can pull mid 1.4s in the summer, then low 1.4s in the autumn, and high 1.3s in the winter, that's what I want. My raceweight should be 3000 lbs. or less, don't know for sure yet.
Stu'sWS6, I'm not calculating for tire growth or converter slippage, but according to the calculator, it says 135 w/the 4.56/29.5 and 136 for the 4.30/28, but realisticaly, it'll probably be 131-134 with tire growth and slippage.
PSJ, I'd like to cut low 1.4s now and high 1.3s in the winter. If I can pull mid 1.4s in the summer, then low 1.4s in the autumn, and high 1.3s in the winter, that's what I want. My raceweight should be 3000 lbs. or less, don't know for sure yet.
09-11-2005, 07:47 PM
#20
The rear end ships out Friday, but will start to be built on Wednesday and finished up probably on Thursday. So I would assume early morning Wednesday would be a good time to make a my mind. If anyone else has any input or those who have already replied would like to add on, please do so that I have a better view and stronger opinion about my decision. Sorry to push this, but I have no personal experience with this, so I'm pretty much trying out a setup that I've never dealt with. I'm fairly new to this, thanks.