24 (or 23) 8.5 x 15 mh slicks?

[168glhs1986]

At what point do 23 x 7.5's become too small?

Is next step 23 x 8.5 or 24 x 8.5?

[forcedfedmopar]

lots of variables. For me it was after i did my holset. est. about 400 whp. I have 3:50 final drive and running high 11s trapping 122 in 4th

[168glhs1986]

lots of variables. For me it was after i did my holset. est. about 400 whp. I have 3:50 final drive and running high 11s trapping 122 in 4th

High 11's at 122 with about 400 hp? Im new to drag racing but shouldn't you be low 11's even high 10's with those #'s?

[4 l-bodies]

Mike,
I have run 11.50's with 23 X 7.5" M&H's in L-body. IMO, 23x8.5 would be more than enough tire for your vehicle. Of course it depends on tranny final drive, RPM of motor, your goals for vehicle, and all kinds of other variables. I didn't have coil overs, so 24" tall tire wasn't an option for me. Just remember bigger tire/wheel combo than you need is just added rotational weight. I'm assuming vehicle is lowered a bit. Ask Brian about having fender contact with slicks. Scary on the big end of track if it happens.
Todd

[shadow88]

Not only is too tall of a tire heavier, it's also lost effective gearing. I would suggest it has more to do with the trap speed than the E.T.

Something that might be helpful... When my shadow would trap about 116-118 with an a-555 trans and 23x7 inch tires it would show about 5800 rpms crossing the line. With the 24.5x8.5 it would show about 5300. The grip at the line was almost the same at that power level and weight.

[forcedfedmopar]

High 11's at 122 with about 400 hp? Im new to drag racing but shouldn't you be low 11's even high 10's with those #'s?

yes, traction in my case is limited with the 23s. I will be going to 24s next year. when my car was making around 300hp the 23s did very well. Now with boost hitting hard in gear it will break the 23s loose at the track in 1-3 gear. I believe that the taller tire will work well for my car. May not be a good choice for your set up. Just sharing personal experience.

[168glhs1986]

yes, traction in my case is limited with the 23s. I will be going to 24s next year. when my car was making around 300hp the 23s did very well. Now with boost hitting hard in gear it will break the 23s loose at the track in 1-3 gear. I believe that the taller tire will work well for my car. May not be a good choice for your set up. Just sharing personal experience.

Gotcha, i thought you were already running 24's. Sounds like a much needed upgrade with that much power / torque.

---------- Post added at 11:49 PM ---------- Previous post was at 11:40 PM ----------

Mike,
I have run 11.50's with 23 X 7.5" M&H's in L-body. IMO, 23x8.5 would be more than enough tire for your vehicle. Of course it depends on tranny final drive, RPM of motor, your goals for vehicle, and all kinds of other variables. I didn't have coil overs, so 24" tall tire wasn't an option for me. Just remember bigger tire/wheel combo than you need is just added rotational weight. I'm assuming vehicle is lowered a bit. Ask Brian about having fender contact with slicks. Scary on the big end of track if it happens.
Todd

Thanks Todd. Was that the masi Glht? I'll probably order the 8.5's soon.

[168glhs1986]

Mods, please move this to the wheel section....

[ShelGame]

When I switched from MT 22x8x15's to MH24.5x8.5x15's last year, I was hoping I'd pick up a tenth in 60' and maybe lose about the same at the top end, with a couple mph lost.

Well, I did pickup a tenth in the 60' and it's much more consistent off the line. While you can see I lost maybe 0.05 in the top end (comparing slips to slips), I actually picked up a mph and go over 100mph now. Overall, my ET is lower now than with the smaller tires. This is all with a 'low' HP Daytona - 2.5 T1, NHRA Stock Class, Mitsu turbo, no IC, etc.

[Pat]

Mike,

For reference, on 23's, I was consistently in the 1.8's with a few 1.7's but would have trouble hooking 2nd gear. On 24.5's, I'm consistently in the 1.6's with a best of 1.63 and have good hook all the way through. I've been faster and way more consistent. Perfect example is the last time out with the Aries...ET'd, 11.04, 11.05, 11.01 and 10.96 on four consectutive runs.

[Pat]

What are your ET targets for the car?

[forcedfedmopar]

I also had great sucess with the 23x8.5s. I was cutting 1.7s consistantly with them until i went bigger (power wise). Then 1.8s were the norm.

[BadAssPerformance]

Moved thread

Wheel diameter and gear ratio coem into play here, think "what RPM is it trapping at going thru the lights at the big end?"

Theoretically for the most effective 1/4 mile gear ratio, you want to be damn near redline at the top of 4th. Here are soem examples for a 6500 RPM target redlind

For a 3.85:1 gearbox (555 or 568)

23" tire @ 6500 RPM in 4th is 123mph
24.5" tire @ 6500 RPM in 4th is 131mph

For a 3.50:1 "hybrid" gearbox (520 gear in 555 or 523 gear in 568)

23" tire @ 6500 RPM in 4th is 135mph
24.5" tire @ 6500 RPM in 4th is 144mph

Reading Shelgame's comments are dead on for a "low hp" application. My T2 Shadow estimated 230-240whp (3.50:1 "hybrid" 555) has run 12.89 with either tire 23x7 or 24.5x8.5... The looooong gear of the "hybrid" works better with the 23's.... it spins the 23's a little out of the hole (5k rpm launch) and on a sticky track I need to almost leave off the ~6500 Stage II LM rev limiter and it dead hooks.

Now a higher HP application... more tire will help

[168glhs1986]

What are your ET targets for the car?

I'm thinking consistant mid 11's without spray. Although 11.2 would be nice to say the Omni is faster down the 1/4 mile than a 2013 Viper SRT

Moved thread

Wheel diameter and gear ratio coem into play here, think "what RPM is it trapping at going thru the lights at the big end?"

Theoretically for the most effective 1/4 mile gear ratio, you want to be damn near redline at the top of 4th. Here are soem examples for a 6500 RPM target redlind

For a 3.85:1 gearbox (555 or 568)

23" tire @ 6500 RPM in 4th is 123mph
24.5" tire @ 6500 RPM in 4th is 131mph

For a 3.50:1 "hybrid" gearbox (520 gear in 555 or 523 gear in 568)

23" tire @ 6500 RPM in 4th is 135mph
24.5" tire @ 6500 RPM in 4th is 144mph

Reading Shelgame's comments are dead on for a "low hp" application. My T2 Shadow estimated 230-240whp (3.50:1 "hybrid" 555) has run 12.89 with either tire 23x7 or 24.5x8.5... The looooong gear of the "hybrid" works better with the 23's.... it spins the 23's a little out of the hole (5k rpm launch) and on a sticky track I need to almost leave off the ~6500 Stage II LM rev limiter and it dead hooks.

Now a higher HP application... more tire will help

Thanks JT. That chart is what I needed. I hope to be trapping around 120 so it looks like 23 x 8.5 may be the tire. I'll probably start off the season with my 7.5's and then move to 8.5's for the rest of the year. We'll see how that goes and if 24's make sense at that point. I'm cutting consistent 1.7's at a low hp of 260 but probably have close to 320 on tap now. So we'll see what that does to the 60' times.

[contraption22]

Mike, I ran 23x8.5's. 1.6x 60 ft. Perfect size for me.

[BadAssPerformance]

I'm cutting consistent 1.7's at a low hp of 260 but probably have close to 320 on tap now. So we'll see what that does to the 60' times.

Yeah, see what the 23x7.5's do with the new power and you should know pretty quick if the taller tire will help more.

Mike, I ran 23x8.5's. 1.6x 60 ft. Perfect size for me.

Thats with an auto tho right? and what race weight?

[BadFastGTC]

Thr chart is assuming full diameter of the tire, correct? When I ran the 23.5 x 7.5 x 15, I went through the traps over 6500. Unless my clutch was slipping....

[contraption22]

Thats with an auto tho right? and what race weight?

Yup, that's with auto. Not sure of the weight. Not drastically different from Mike's car I'm sure. Maybe a bit heavier.

[shadow88]

Thr chart is assuming full diameter of the tire, correct? When I ran the 23.5 x 7.5 x 15, I went through the traps over 6500. Unless my clutch was slipping....

Maybe....What transaxle?

[BadFastGTC]

Maybe....What transaxle?

568 in Sledgehammer. I thought I saw 6800 going through the traps, but that was a long, long time ago. 12psi in the slick makes a very small overall tire diameter, even at 120+.

---------- Post added at 02:14 PM ---------- Previous post was at 02:13 PM ----------

Yup, that's with auto. Not sure of the weight. Not drastically different from Mike's car I'm sure. Maybe a bit heavier.

Nah, you're losing weight there buddy!