Tire weight

[Kurlon]

Random fun question for the day: Comparing matching make/model race tires, is there much of a weight difference between a 180 and 160 rear?

[csmutty]

Kurtz?

[Degsy]

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About 3.5lb

[Degsy]

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Also depends on manufacturer.

[Kurlon]

Ok, so enough difference to be significant then given it's all circumference weight. Now I just need to get some moment of inertia numbers to know if a 180 tire on a 5.5 x 17 cast mag rim is better than a 160 on a forged aluminum 4.5 x 17 rim...

Where did I put that aftermarket wheel comparison article?!

[csmutty]

OH you mad scientist! More throttle less brake man.

[lrrs313]

Ok, so enough difference to be significant then given it's all circumference weight. Now I just need to get some moment of inertia numbers to know if a 180 tire on a 5.5 x 17 cast mag rim is better than a 160 on a forged aluminum 4.5 x 17 rim...

Where did I put that aftermarket wheel comparison article?!

Don't forget to factor in that a lot of the manufacturers aren't making their top of the line tires in the 160, i.e. Dunlop's NTEC.

[Kurlon]

Don't forget to factor in that a lot of the manufacturers aren't making their top of the line tires in the 160, i.e. Dunlop's NTEC.

Dunlop is making a 165 rear slick for Sumo and 250GP use, the KR108. For the limited time I ran them, and at the slow lap times I was pushing the Dunlop slicks on my KTM felt good, no idea what they were... AFAIK Bridgestone offers a 165 rear slick as well, and I liked the feel of my BT090s. I don't recall what Pirelli is offering but in the past they offered 110/150s I think, the Supercorsa SC in a 110 front stuck like glue too so I think there are still some options out there for smaller tires. On the flip side if the motards have decided 170s and 180s are worth the weight with only 50hp at the rear wheel, maybe I shouldn't be concerned?

[csmutty]

Dunlop is making a 165 rear slick for Sumo and 250GP use, the KR108. For the limited time I ran them, and at the slow lap times I was pushing the Dunlop slicks on my KTM felt good, no idea what they were... AFAIK Bridgestone offers a 165 rear slick as well, and I liked the feel of my BT090s. I don't recall what Pirelli is offering but in the past they offered 110/150s I think, the Supercorsa SC in a 110 front stuck like glue too so I think there are still some options out there for smaller tires. On the flip side if the motards have decided 170s and 180s are worth the weight with only 50hp at the rear wheel, maybe I shouldn't be concerned?

170 is the supermoto dunlop tire that some run. Other than that everyone that I know runs a 160 or 165. No 180s in the motard grids. And if you can find a motard with 50 hp...lol Most are pushing 60whp or have exceeded it.

[Kurlon]

I'd love to see some dynos of 450s with 60hp at the rear wheel, I was under the impression that it was damn hard to achieve and they were grenades when you go there?

[lrrs313]

I'd love to see some dynos of 450s with 60hp at the rear wheel, I was under the impression that it was damn hard to achieve and they were grenades when you go there?

Motards this year seem to have made their swing back to the way it was a few years ago -- lots of guys running seriously built motors and blowing them up a lot. Seems to be a cycle -- the guys running built motors will get sick of spending the money, then the class will be left to guys running semi-stock for a bit, then people will start building motors again, etc.

EDIT: Don't the Aprillias run a 180 rear? I thought the 550 came with a 5.5 rear wheel and a 180 stock.

[lrrs313]

Dunlop is making a 165 rear slick for Sumo and 250GP use, the KR108. For the limited time I ran them, and at the slow lap times I was pushing the Dunlop slicks on my KTM felt good, no idea what they were... AFAIK Bridgestone offers a 165 rear slick as well, and I liked the feel of my BT090s. I don't recall what Pirelli is offering but in the past they offered 110/150s I think, the Supercorsa SC in a 110 front stuck like glue too so I think there are still some options out there for smaller tires. On the flip side if the motards have decided 170s and 180s are worth the weight with only 50hp at the rear wheel, maybe I shouldn't be concerned?

Correct, and they are all good tires, and I never had an issue with the Dunlop or B-Stone slicks on my motard. I was just saying that, since you're considering different size wheel/tire and weighing the benefits, you need to factor in the more updated tire constructions being offered for the larger tires (NTEC, Bridgestone's new "NTEC beater," etc). The added grip MAY offset some of the weight penalty.

I could be miles off base, just an observation.

[Chippertheripper]

I'm not wild about the Dunlop 170. I was expecting a Dunlop to never skip a beat, but the thing moves quite a bit. It's predictable, but it's not on rails.
I think a 160 would suit your purpose better...based on nothing more than gut.

[R7]

EDIT: Don't the Aprillias run a 180 rear? I thought the 550 came with a 5.5 rear wheel and a 180 stock.

Yes, the SXV 450/550 have 5.5" rear wheels and 180 is the standard tire

[csmutty]

I'd love to see some dynos of 450s with 60hp at the rear wheel, I was under the impression that it was damn hard to achieve and they were grenades when you go there?

I know Trevor Chiappisi has about 60 or more, Block has about that or more, Shaw is really close to that, Cavanaugh has about that, mine is a little short of the 60 mark, etc.

[Mr. Kurtz]

Diablo Superbike slicks & Supercorsa DOT are 12.8 pounds, same for 160/60 & 180/55 rears. Not 100% sure how that works out, but that's what my technical docs say...

[Kitt]

Ok, so enough difference to be significant then given it's all circumference weight. Now I just need to get some moment of inertia numbers to know if a 180 tire on a 5.5 x 17 cast mag rim is better than a 160 on a forged aluminum 4.5 x 17 rim...

Where did I put that aftermarket wheel comparison article?!

get off the bench racing and ride it like you stole it.

[Pittenger5]

Motards this year seem to have made their swing back to the way it was a few years ago -- lots of guys running seriously built motors and blowing them up a lot. Seems to be a cycle -- the guys running built motors will get sick of spending the money, then the class will be left to guys running semi-stock for a bit, then people will start building motors again, etc.

EDIT: Don't the Aprillias run a 180 rear? I thought the 550 came with a 5.5 rear wheel and a 180 stock.

Wow ... almost makes me glad I'm not racing this year. Almost.

[nt650hawk]

5" rim with a 160-165 is a perfect combination. Trying to squeeze it on a 4.5 you lose a bit of the side patch. I would think about a 150 for the 4.5" rim.

[TheIglu]

So who makes a nice sticky 150 race tire?

[nt650hawk]

BT-090 Pro
110/70HR17 090 STD 23.3 4.4 (3.00) 2.75-3.50
120/70HR17 090 STD 23.8 4.7 (3.50) 3.00-3.50
140/70HR17 090 PRO 24.7 5.5 (4.00) 3.50-4.50
150/60HR17 090 PRO 24.4 6.1 (4.00) 3.50-4.50
160/60HR17 090 PRO 24.9 6.5 (4.50) 4.00-5.00
150/60HR18 090 PRO 25.2 6.2 (4.00) 3.50-4.50
• DOT Approved Race Tire
• High Grip Compound for
Lightweight Bikes
• Tread Pattern Optimizes
Rigidity



250 GP Slick
120/600R17 R01Z YDC / YCX 23.6 4.6 (3.75) 3.50-3.75
125/60OR17 R09AZ YCY 23.6 4.6 (3.75) 3.50-3.75
165/630R17 R02Z YDC/YCX/YCY 24.8 6.5 (5.50) 5.00-5.50
155/635R18 MR02Z YCX 25.0 5.9 (4.50) 4.00-4.75

[KB]

get off the bench racing and ride it like you stole it.

Says the man who all but forgot where the track was.

KB

[SVRACER01]

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165 n tech should be available next year

[a13x]

Wow ... almost makes me glad I'm not racing this year. Almost.

Almost. Pretty sure our two old 2005 52hp RMZ 4-speed would be doing just fine.

[Karaya One]

Bridgestone still makes this size - 150/60HR18 090 PRO ?

Gotta be FZR600? Are there any left still on the track?