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ContiClassicAttack actual dimensions

2318 Views 36 Replies 7 Participants Last post by  crazypj
I am building a cafe racer with a combination fork brace/fender mount/caliper hanger. I need to know tire dimensions/clearances to complete this part of the project, but don't want to actually purchase the tires until the project is closer to completion, so the tires are fresh. (I've been "working" on this bike for nigh on 30 years, and it might be a couple more years before it's actually ready for tires.) Since no tire company other than Avon seems to publish actual measurements of their tires, I was hoping someone here could take a couple of measurements for me. The bike has an 18 x 2.15 Sun rim on the front. At this point, I am considering the 90/90 R 18 ContiClassicAttack and the Michelin 100/90-18 Pilot Activ. If anyone out there has either of these tires and can measure the actual overall diameter and width, I would greatly appreciate it. Thanks.
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Since no tire company other than Avon seems to publish actual measurements of their tires, I ...
Sure they do... u just don't know where to look
OK I actually cant find the link anymore for continental... so here is my copy.
specs start on page 276
on road radials on page 282
conti 18in classic attacks on page 283


You might consider writing to the company for tire info as well...
BTW, the two tires you are looking at are different. one is radial, the other bias.
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The 90/90r18 conti classic attacks fit a 1.85 to 2.5 inch rim.
I'm not sure where or how you are reading the fitment chart...


30 year build???? And I thought I was a bad procrastinator
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Oh yeah... forgot that the numbers listed there are a typo... if u notice they duplicate the 100 sized tire just below it. I ran into the same issue when I was researching myself.

I basically took the dimensions from the conti go tire (in the bias ply section) for the same sized tire... as a guide...

I have the tire mounted if you want me to measure.... I doubt there's gonna be much difference.
But since u asked originally, I will measure tonight when I get home...
I was looking at page 283, which shows acceptable rims for the 90/90 R 18 Classic Attack to be 2.50 and 2.75. What page did you copy above? And yes, a 30 year build is ridiculous, but that's my life.
From continentals current listing 2021 for classic attacks
I notice that all of the measurements in the PDF catalog you sent for the 90/90 ClassicAttack and the 100/90 RoadAttack are identical. That can't be right. My guess is the the 90/90 is, in fact, smaller in every dimension. Your ruler will rule!
That's what I said... the dimensions are a typo... as well as the recommended rim widths in the 2015 tech catalog I posted... basically they copied the exact dimensions of the 100 size tire in the next line.
so for dimensions i just went by the dimensions for the conti go bias tires at the 90/90 size. It's nearly the same as I recall.
I already knew the 90/90 tire would be fine for my 1.85" front wheel.
i got behind today but will get the actual measurements tomorrow but it's gonna be within mm's of the conti go tire
So your width will vary a little depending on the size rim u use.
On my 1.85" rim the width at the widest point is about 3.6 inches...
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Looks like a huge range of rim widths...
In fact 2.15 appears to be right on the middle of the range!

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I wonder what's the best way to measure diameter... I can think of a couple ways.... all with their own drawbacks

It'll be an estimate unless I dismount the wheel.
BTW. I have about 1/2" clearance to my fender. Now I'm not sure if the fender flexes a little as well but I've topped the bike out at redline in top gear (probably only around 110 or so) repeatedly on the track and I don't see any evidence of rubbing.
Conti road attack 3 are being offered with a $50 prepaid visa card.
i didnt see the bit about racing the bike. so why is this thread in the “racing” section? boring...
Good point...

So, this'll be my last contribution...
a tape wrapped around the circumference measured 76.25". 24.2" diameter.
Tire might have been low on pressure from sitting... so take the measurements as it is, an estimate.
Compared to continental's conti go dimensions in the same size, 619mm vs 615mm. Well within the error of my measuring method.

Measuring any other way i had available to me was way more inaccurate. +/- up to 1/2 to 3/4" and really just a guess due to parallax error.
Thank you very much for getting that measurement, JCW. Sounds like a hassle. That OD is a bit small for this bike, I think, which makes the 100/90 R 18 RoadAttack the best choice for me. So far as putting my opening query on the racing forum, dirtchecken, the tires in question are, from what I understand, more common on the track (at least for track days) than they are on the street. I needed an answer to the question, and sure enough, JCW was here to answer it.
No problemo
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