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R75/6 front tire rubbing

eurotourer

New member
I just picked up ‘74 R75/6 that I am restoring. The front tire rubs so bad on the fender bracket that the bike is hard to push. It’s an Avon Roadrunner AM20 in the correct size. The width is 4.13 inches. A Metzeler ME33 is only 3.65 inches and would be perfect if it was still available.
Does anyone have a /6 without this problem and tell me what tire to get.
 
Hi Eurotourer,

The front should be 3.25" x 19". The tire is obviously too wide.

You can find this tire size from Metzler and Continental, among others.

I hope this helps.

Best.
Brook Reams.
 
I won’t tell you what to get, but my /6 has Avon Roadriders in the stock size mounted and I’m happy with them. 4 sets so far.
The largest tire that would fit was tried once and I could not wait for them to wear out and took them off. AirHeads with stock sized tires handle quite well.
I just mounted Continental Road Attack tires to a K1100RS and after 2500 miles am very happy with them. I hope that they or something similar will be available in 3.25 x 19 & 4.00 x 18 sizes for the /6.
Bill
 
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Hi Eurotourer,

The front should be 3.25" x 19". The tire is obviously too wide.

You can find this tire size from Metzler and Continental, among others.

I hope this helps.

Best.
Brook Reams.

It is a 3.25x19 but made in 2004. The ridge on the side of the tire is unusually thick.
 
I would have thought that the build process in 2004 is the same today, but using a tire that old should really be out of the question. Get a newly built 3.25x19 tire and things should be fine.

Also wondering...is the front tire centered in the fender? Could the wheel be mounted slightly offset or is the fender damaged in anyway?
 
Everything seems to be straight but just by looking at the front of the bike it’s obvious the tire is too wide.
I have a ME33 on my /5 and it looks and actually is narrower, both 3.25x19.
I just get a newer type Metzeler and hope it’s not wider than the ME33.
 
From my memory, the brace that is part of the fender changed from the /5 days to some point in the /6 era. With the smaller fender brace, tire choice was critical.

There's no real standard in terms of the width of the tire...they'll be different between the various manufacturers. Get a good quality tire in the right size and things should be fine.
 
That’s it. The 3.25x19 they list gives me 0.2 inch more clearance and will be enough.
Looks like they changed the dimensions.
Thanks for the link.
 
I just installed a new Avon Roadrider AM26. Much thinner than than the AM20, both 3.25x19 and plenty of clearance. Problem solved. The AM20 looks like it was supposed to be a rear tire. When I picked up this barn find I assumed the front brakes were frozen. Never seen anything like this.
 

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I just installed a new Avon Roadrider AM26. Much thinner than than the AM20, both 3.25x19 and plenty of clearance. Problem solved. The AM20 looks like it was supposed to be a rear tire. When I picked up this barn find I assumed the front brakes were frozen. Never seen anything like this.

I seem to recall mounting Avon Roadriders and some sizes were reversible. They have two indiacators; this way for the front and opposite if mounting on the rear.
 
Install /7 fender brace. They allow the installation of a wider tire -

I did that, did not like the way the wider tires changed the way the bike handled on mountain roads and returned to the stock sized tires.*

62795E45-C7E5-45CC-A976-26BB70CBE48B.jpeg
Edit; After buying the bike & getting it to a reliable running condition I replaced the rear shocks. That led to the front suspension upgrade. That led to ...
Gold Valves in the forks, Flanders "S" bars with bar end mirrors, Heinrich tank, Boyer ignition, Siebenrock 1000cc kit, heads/carbs reworked a bit, Works shocks, otherwise it's bone stock.

* Edit; Just looked at this again and my reply seems a bit condescending.
I like the fat tire look but most riding for me is in the hills and mountains and the wider tires (the ones I had mounted) defeated the improved handling I had spent money on upgrading the suspension.
Bill
 
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I have a 1975 R90/6 that I’m getting back to roadworthy after 10 years dormant. It has front tire 3.25-19 and rear tire that is 4.00-18. The front tire is rubbing on the fender’s metal bracket slightly. The tires being old as well, I bought new tires: front sized 100/90/19 and rear sized 120/90/18.

Did I buy correctly sized new tires?

Thank you so much for your guidance!!!


Sent from my iPhone using Tapatalk
 
Not sure which tire you meant. Is the old 3.25 inch tire rubbing or the new 100/90 tire?

That bike was originally fitted with inch size tires. They are still available. Why did you get metric sizes?
 
The old 3.25 was rubbing on the front fender’s metal bracket. I bought the new tires based on what was recommended to me by a guy who owns a classic auto/moto repair shop. He was trying to help me out because I’m not familiar with the tires. He thought the old 3.25 was too big to begin with. I can’t find a manual or resource that tells me what size tires the 1975 R90/6 takes/requires. Is perhaps the fender’s metal bracket the problem? Does not look bent or crooked though...let’s oks true.


Sent from my iPhone using Tapatalk
 
A 90/90/19 metric sized tire will not rub. A 100/90/19 is considered to be the nearest metric equivalent to the original 3.25- 19, but some tires have a wider edge profile.
 
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