VW Golf 1.8T: Tire Recommendations

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Rabbit Farmer
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VW Golf 1.8T: Tire Recommendations

Post by Rabbit Farmer »

In an effort to...
1. keep my transmission together
2. give me enough traction so that the 3 mile hills aren't 5 miles on my odometer
3. reduce the price of tires
4. increase my mechancial advantage so I not a 2 gear car on the hill

I am installing a 6-speed over the winter (unsure if I am changing the final or not) and getting low profile 245-xx-15 tires.

Right now have a 5 speed and 235-40-17. A 2" shorter rim should help with the acceleration on the hill. I find that I only have 2 gears on the hill (usually 2nd and 3rd) and at the track (3rd and 4th); also I am far from being close to the top of the higher gear.

Why a six speed? VW 5-speeds are a little weak for the power that I have (the 115 wHP) wherein people are running stock 6-speeds with 475wHP (wow!). Plus, I will have more gears to pick from. I really need to look at the MPH range in each gear to determine if I want to change the final drive while installing the LSD.

Anyway, long story to get to my single question. I plan on running low profile sticky (unsure if that means DOT R or "Race") 245-15 tires. Suggestions? More than likely I will continue to run the 17" tires at the track as I have a lot of life left on two complete sets of RA1s. Unsure if I want "race" tires or DOT for the hillclimbs. With race tires I would have to fun in a P class... something that I am doing right now with the SP car so that I can have all my runs in a single class during the year regardless of which car I drive at the events.

Options for DOT R and race tires?

Right now the car is 300wHP; I might up this to 350wHP over the winter (just need to change a sensor and dyno it again) if I feel the 6-speed gearing and tires would make for a quicker run up the hill.

Thanks
Steve
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walterclark
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Re: VW Golf 1.8T: Tire Recommendations

Post by walterclark »

I am extremely happy with the Khumo V710 which is permitted in street prepared. I am on my second set. Ask Earl how he likes them - the only change to his car has been from Victoracers to V710 (you know Earl hasnt changed) and look at his improved times. Don runs them too.

Problem is in looking at V710 245 widths, the wheel diameter and profiles available are limited and in the 16-17" wheel (no 15" in 245) they both come in at around 24.6-24.7" outside diameter. Pretty much the same story with Hoosier A6. The R6 does have a 245-15" size but the diameter is 24.8" (not sure the R6 is best for hillclimbs) so going down in wheel diameter doesnt get you a smaller rolling diameter tire. To get to a smaller rolling diameter you need to go narrower - to 225.

The Toyo competition tires show the same issue.

To get a small diameter 245 tire in the "DOT-R" you may have to go to a full slick like the Hoosier road racing radial. They have a 23.5 x 11.0R-16 which is a bit wider than 245 and has a 23.6" diameter which is about 3% smaller, and a 23.0 x 9.5R-15 which slightly narrower and has a 22.9 diameter which is about 6.5% smaller.

I found this info for the GTI 1.8T 5-speed tranny: EGQ,FBW 1st 3.300 2nd 1.944 3rd 1.308 4th 1.029 5th 0.837 F 3.938

I found this info for a GTI 6-speed tranny:

Image

If that is what you are getting then to move a full gear up between the new ratios and a 6% change due to tires you may just get there.


Edit: I made up a little spreadsheet to compare the above. Out of the box the 6 speed has about 6% higher ratios. If you wanted to set it up so (new=old) 6=5, 5=4, 4=3 then you would need another 20% increase in ratios: a 20% reduction in tire diameter or a combo of R:P ratio increase and tire diameter reduction since a 19.8" diameter tire probably isnt in the cards.
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Mopar 151
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Re: VW Golf 1.8T: Tire Recommendations

Post by Mopar 151 »

A less informed post - basically, this sets you up with my dillemma - which, in my case is a 3-4 drop from 6.01 to 4.33 overall. (4,33 final, 1.39 3rd) Even with the "torque monster" I have under the hood, only the perfect shift, on the perfect run, in perfect "horsepower air", will the engine not lay down on the 3-4 shift at Burke. My results under those circumstances are well known.....
Doing the %'s you will be slightly better off than I - but not much.
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Re: VW Golf 1.8T: Tire Recommendations

Post by Mopar 151 »

OK, more on domestic "Fo-speeds"
Muncie wide ratio gearsets have a 1.46 3rd, the coveted "close-ratio" is 1.28 3rd gear

The "Daytona" gearset for the 18-spline is rare as hen's teeth - but it has a 1.29 3rd gear! And it would mean 300 rpm less "drop" on the 3-4 shift
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Re: VW Golf 1.8T: Tire Recommendations

Post by Mopar 151 »

More ratios: I think I want a t-10..... And I think I know why Butch was holding out (with a [blech!] Saginaw) 'til he could do a Jerico
Trans Type First Second Third Fourth Fifth Sixth
BORG WARNER T10 2.23 1.76 1.30 1.00 - -
BORG WARNER T10 2.43 1.64 1.24 1.00 - -
BORG WARNER T10 2.64 1.76 1.35 1.00 - -
BORG WARNER T10 2.64 1.64 1.24 1.00 - -
BORG WARNER T10 2.88 1.76 1.35 1.00 - -
BORG WARNER T10 2.88 1.91 1.35 1.00 - -
BORG WARNER T10 3.42 2.28 1.46 1.00 - -
BORG WARNER T10 3.44 2.28 1.46 1.00 - -
BORG WARNER T5 2.95 1.94 1.34 1.00 0.63(TBI) -
BORG WARNER T5 2.75 1.94 1.34 1.00 0.74(TPI) -
BORG WARNER T56 2.66 1.78 1.30 1.00 0.74 0.50
BORG WARNER T56 2.97 1.94 1.35 1.00 0.84 0.62
BORG WARNER T56 3.36 2.07 1.35 1.00 0.84 0.62
MUNCIE M20 2.56 1.91 1.48 1.00 - -
MUNCIE M20 2.52 1.88 1.46 1.00 - -
MUNCIE M21 2.20 1.64 1.28 1.00 - -
MUNCIE M22 2.20 1.64 1.28 1.00 - -
M-12 2.97 2.07 1.43 1.00 0.84 0.56
SAGINAW (4spd.) 3.11 2.20 1.47 1.00 - -
SAGINAW (4spd.) 2.85 2.02 1.35 1.00 - -
SAGINAW (4spd.) 2.54 1.80 1.32 1.00 - -
SAGINAW (4spd.) 2.54 1.80 1.44 1.00 - -
ZF6 3.07 1.80 1.43 1.00 0.71 0.59
ZF S6-650 5.79 3.31 2.10 1.31 1.00 0.76
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Re: VW Golf 1.8T: Tire Recommendations

Post by Rabbit Farmer »

All good information. I need to look at what is available in 15's (I just assumed there was a lot) vs. 16's. Looks like a change in final might be in order. Thanks.
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Re: VW Golf 1.8T: Tire Recommendations

Post by sachilles »

Hoosier makes the A6 in 275/35/15, which would require a wider rim, but that is only a 23" diameter tire. The 275/50 is 25.5
https://www.hoosiertire.com/rrtire.htm
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Re: VW Golf 1.8T: Tire Recommendations

Post by walterclark »

sachilles wrote:Hoosier makes the A6 in 275/35/15, which would require a wider rim, but that is only a 23" diameter tire. The 275/50 is 25.5
https://www.hoosiertire.com/rrtire.htm
The widest I see people racing Golfs with are 245 and I saw one guy claiming he autocrosses with 255 - my guess is he has about as much suspension travel as my lawnmower. My guess is clearance is an issue above 245 and 275 isnt going to happen without a lot of changes in the wheel well area.

I based my writeup on the 245 width that Steve expressed interest in as I assumed he has determined this is about the limit for width on his car otherwise with traction being the major limiter of straight line acceleration in his car he would do wider if that were practical. If he could stuff a 23" diameter 275 series Hoosier DOT-R under the front fenders that would be awesome.
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Re: VW Golf 1.8T: Tire Recommendations

Post by sachilles »

Some of the impreza folk have started utilizing the 275/35 15, and it is indeed a tight fit, and typically need to firm up the suspension a bit, as they definitely don't fit within the body work. As well as go with a custom backspace wheel. The firmer spring rates might not be a good fit for a hillclimber though. Obviously very different cars to begin with, but seeing the power he can put down with that car, I have a tough time seeing 245's(or equiv) as being enough even with the stickiest non dot compound. I certainly would not have fun mounting those tires on a rim either. :lol:
Sure do look sexy though.
Image

I'd be curious to see how the non dot hoosier would hold up, as I'm noticing they(radials) were intended for the formula atantic series, while the bias ply were intended for EP and GT3. They'd probably warm up quickly, as your car would be heavier than the original car they were intended for.
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Re: VW Golf 1.8T: Tire Recommendations

Post by walterclark »

The Street Prepared classification says this: "Rim size may be changed. Tire size is free but the tread may not be seen from above. Tires must be DOT approved. Wheel openings shall retain their original contour when viewed from the side." That Subie could not run at hilllcimbs in SP without adding some fender flares to cover the tires. My guess is to run a 275 on Steves Golf without suspension component mods to permit maintaining the stock wheel to hub-bearing centers would require a very low offset wheel and lots of tire sticking out -- doing so could make a mess of things that are important to hillclimbing by moving scrub radius way positive (increasing torque steer, and feedback but at the expense of increased steering effort and steering wheel response to bumps) not to mention added bearing and bushing stresses and fender and/or wheelhouse interference.
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