Differences in weights of tires

[soareyes]

While researching tires I noticed that there can be as much as 5 lbs. difference in tire weight between manufacturers in the same size tire (195/50/15 in my case). How significant would 5 lbs. difference be on each corner of a Seven? Would a relatively inexperienced driver like myself notice it on the street or track?

I remember seeing a TV car show last year where they dynoed a car before and after upgrading to a larger (and heavier) wheel/tire combo and they lost something like 10 or 15 hp!

Stan

[Roll a 7]

When I switched from Avon ACB 10s to Kumho, which are about 1" wider at each corner, my car gained nearly 40 pounds. I can definitely feel the difference in the steering, it IS heavier! The trade off is much greater adhesion. I'm sticking with the Kumhos.

[Doug Liedblad]

Stan

Yes, you do notice the difference in the weights.

Lighter wheels and tires (stickier too) made a huge difference in my lap times at Willow.

Doug

[moosetestbestanden]

my car gained nearly 40 pounds

10 pounds per tire? Whoa.

[Sean-og]

When I switched from Avon ACB 10s to Kumho... ...much greater adhesion.

Wow. From everything I've read, I was under the impression that the only tire with greater adhesion than an ACB10 was slicks, given dry roads.

[slomove]

Nice wheel setup does make a difference which I noticed switching from the superheavy 15" Bridgestone S03 on stock rims to 13" ACB10 on RealWheel rims (total difference about 70 pounds!). But I still drive the Bridgestones on the road.

A difference of 20 pounds as you mention, I don't know. May be subtle.....

But whoever wrote that article about dyno gain by lighter wheels is talking bollocks. How's that supposed to work?

Gert

[magnusfeuer]

I haven't read the article, but I think they confused more HP/torque with the increased acceleration/braking power you get from lighter wheels.

This is since you have less inertia (in the wheels) to fight when you floor either of the two rightmost pedals.

/Magnus F.

[soareyes]

Nice wheel setup does make a difference which I noticed switching from the superheavy 15" Bridgestone S03 on stock rims to 13" ACB10 on RealWheel rims (total difference about 70 pounds!).
Gert

I remember picking up one of your wheels with the Avons, and I swear you must use helium instead of air!

Concerning your S03's, I think you are using 195's in front and 225's in the rear? Are you still happy with those sizes vs. running 195's front and rear?

Stan

[slomove]

Yes, well, I am happy like anybody who never tried something else. Even the ACB10 have a similar width difference (the rear 8" are even equivalent to 245 size). But I just followed other folks advice.

You should better talk with some people who have more experience. Or look up a million posts on Blatchat.

Gert

Concerning your S03's, I think you are using 195's in front and 225's in the rear? Are you still happy with those sizes vs. running 195's front and rear?

Stan

[soareyes]

Or look up a million posts on Blatchat.
Gert

Yes, a search turned up lots of info on Blatchat, but not till I remembered its "tyre", not "tire"!

Stan

[Roll a 7]

The Kumho Ectsa V700 fronts are size 215/50X13 and weigh 20 pounds each. The Kumho rears are 235/45X13 and weigh 22 pounds each. The Avon 7.00X13 ACB 10 fronts weigh 10-11 pounds each and the rear 8.00X13s weigh 12 pounds each according to Avon. The Barnby wheels I'm using weigh an average of less than 7 pounds each and are lighter than the SLR wheels. I can feel the weight/grip difference when driving the car, especially at low speeds

The Kumho tires are about 1" wider than the Avon ACB 10s and a much softer compound (ACB 10s for Caterhams are NOT a soft compound). I think the Avons feel kind of slippery/greasy in comparison. I used both last time @ Streets and the Kumhos were several seconds per lap faster, in my opinion. BUT, they don't last nearly as long. On the other hand they are about the least expensive ultra high performance tire I could find!!

I've also used both extensively in autocross and the Kumhos are worth 2-3 seconds on a sixty second lap.

BY the way, Jon Stokes has about twenty half used ACB 10s that he would like to off. He does not believe in running them out completely. No idea of the cost, but, it's a rather, limited market..... I'll ask Jon and post them here.

[Rich H]

The Kumho Ectsa V700 fronts are size 215/50X13 and weigh 20 pounds each. The Kumho rears are 235/45X13 and weigh 22 pounds each. The Avon 7.00X13 ACB 10 fronts weigh 10-11 pounds each and the rear 8.00X13s weigh 12 pounds each according to Avon. The Barnby wheels I'm using weigh an average of less than 7 pounds each and are lighter than the SLR wheels. I can feel the weight/grip difference when driving the car, especially at low speeds

The Kumho tires are about 1" wider than the Avon ACB 10s and a much softer compound (ACB 10s for Caterhams are NOT a soft compound). I think the Avons feel kind of slippery/greasy in comparison. I used both last time @ Streets and the Kumhos were several seconds per lap faster, in my opinion. BUT, they don't last nearly as long. On the other hand they are about the least expensive ultra high performance tire I could find!!

I've also used both extensively in autocross and the Kumhos are worth 2-3 seconds on a sixty second lap.

BY the way, Jon Stokes has about twenty half used ACB 10s that he would like to off. He does not believe in running them out completely. No idea of the cost, but, it's a rather, limited market..... I'll ask Jon and post them here.

I also run Barnby wheels and ACB10s and observe that the ACB10s have to get hot to work - that takes maybe one to three laps or so on a reasonably warm day, depending upon track traffic and the tires' age. I've been told that there are softer compound ACB10s available in the Caterham sizes, but I haven't tried to find them to buy. Slicks would be faster in any case.

[magnusfeuer]

I've run Kumho V700 Victoracer (older version), V710 slicks (DOT legal, barely), and V700 ECSTA (newer version) on the Caterham. 15 inch and I believe 215/55 (but memory may fail me here).

The slicks by far outperforms both other tires. The Victoracer is more of a track tire with very shallow treads even when not shaved. It works fine for street use, but wears out quite fast. The ECSTA seems to be more of a street tire that can be used on the track. I went directly from the slicks to the ECSTA during the last track event, and there was a huge difference in favor of the slicks.

I ran the slicks on the roads as well, and they are OK. They do however have a tendency to aquaplane at 30MPH, which I noticed during a rainstorm one late night.

All these tires are very good, and fairly cheap. I use to pay approx 115-150 per tire with heat cycling at tire rack. Unless I find something with comparable grip in the same price range which is lighter, I am staying with them.

/Magnus F.

[moosetestbestanden]

Note that Brad's tires are a full inch wider than the others mentioned. That's a lot more contact patch, particularly for a small car.

John was down in the low 1:11s at the Streets on the Avon Slicks last trip up there and in the 1:14s on ACB10s. Same car, same driver, same conditions.

My experience on the ACB10s echos that mentioned. They get much better when they're hot.

Surface area on the ground makes a huge difference. It's one big reason why modern cars "perform" so much better than older ones; they're using a *lot* bigger tires.

[Roll a 7]

Mr. Jon Stokes is offering some of his new and used AVON ACB 10s to 7 owners. A set of new ACB 10s is around $750 and Jon has one set available. He also has a set that has been heat cycled once (20 minutes?) and is available, price negotiable. There are also 3-4 sets of used ACB 10s that he describes as 50-60% used that can be had for $100 per set (4 tyres). If you want to try ACB 10s at a really good price this is as good a chance as you are likely to get. Jon can also mount and balance the tires for an additional charge. I am assuming that the tires are the 7.00X13 fronts and 8.00X13 rears.

If you are interested give Jon a call @ Stokes Performance Tire in Santa Monica @ 310-393-0767. This is where the STARS get their tyres and you should too!! Seems like a good deal to me.....