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MPH increase 26" to 28" ET street radials?

Old 03-17-2010, 09:16 PM
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Default MPH increase 26" to 28" ET street radials?

I'm stepping up to a 28" radial hoping to get some more consistant launches but will it increase my MPH? My buddy that has been racing for 20 years is telling me that I will pick up a ton of MPH with the taller tires. Anybody made the same switch and have any results?
Old 03-17-2010, 09:44 PM
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I'm not that knowledgable about this but it seems like you are losing some gearing advantage (maybe similar to going from 4.10s to 3.73s) which would decrease mph. At the same time you would loose less power to spin, etc and be able to launch harder which would help.

So overall I would think you would loose some mph unless you're running out of gear. I was running out of gearing so it increased my mph.
Old 03-18-2010, 01:00 AM
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Are you switching from a bias ply tire to a radial tire? If so, then yes, typically you'll gain some mph but that's usually only if you're staying with the same diameter.

Kinda hard to say if you'll gain, stay the same, or lose mph. Just kinda depends where you're at with the rpm's, gearing, launch etc...

Mike
Old 03-18-2010, 08:57 AM
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The only way I can see it increasing your MPH is if you are hitting the limiter before the traps with your 26" tires.
Old 03-18-2010, 11:36 AM
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Yup, if you are on the limiter otherwise you will probably loose 1-2mph.
Old 03-18-2010, 01:12 PM
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Different car altogether, but I also lost MPH.

Al
Old 03-18-2010, 01:51 PM
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I'd say it could potentially gain MPH but lost ET. It depends on shape of the torque curve, where you are on the curve right before the traps (which is a function of which final gear you have).

Basically , depends on the set up.
Old 03-18-2010, 03:55 PM
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Originally Posted by 2ktransam
I'm stepping up to a 28" radial hoping to get some more consistant launches but will it increase my MPH? My buddy that has been racing for 20 years is telling me that I will pick up a ton of MPH with the taller tires. Anybody made the same switch and have any results?
taller tire should be more consistent.
Old 03-18-2010, 05:48 PM
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I lost 2mph going from a 26 to a 28 inch tire.
Old 03-18-2010, 06:09 PM
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Anyone gain ET?
Old 03-18-2010, 06:23 PM
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Originally Posted by Mean87SS
Anyone gain ET?
If you've got more to go to get to redline after traps, then you should reduce ET .
Old 03-18-2010, 09:15 PM
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Like others have said, it depends on your set up and what you've switched from. If you were on a 26" radial and not hitting the limiter thru the traps, then you will most likely loose MPH with the 28" radial.
If you were on a 26" bias ply and/or hitting the limiter, you should gain some MPH. Either way you should 60' better(and et better) on the 28's if you were experiencing a lot of tire spin with the 26's
Old 03-18-2010, 09:55 PM
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I'm going from a 26" et street radial to the 28". I made about 15 passes on the 26" tire last year and only hooked one time which I had to roll into the throttle to get it to stick. My shift points are at 6500 which is where the power starts to fall off quick and I was going through the traps at 6900 in third. I'm hoping it will launch more consistent and stay in the power band better out the back door which should pick up some mph. I guess we will find out on Saturday.


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