MAK

I'm currently running Conti Top Contact II 37mm tires on my +/- 10 year old 520 with planet bike fenders. The tires fit but the clearance between the tire and fender is extremely tight. Even on pavement if I get a pebble stuck in the tread it scrapes the fender and sounds like arcing electricity. Without realizing the potential problems, I rode a muddy trail and both wheels literally seized up making the ride a disaster.

I'm assuming that I need to drop to 35 or even 32 mm tires. Can anyone recommend a quality 32 or 35 mm tire that has a lower profile than most so I can add clearance? Yes, the fenders are at their highest adjustment. Also, since I'm a big guy, I tend to run my tires at or close to maximum recommended psi.

I have been looking at bicyclerollingresistance.com which lists heights of those tires tested. Even if I go to 32mm Schwalbe Marathon Green Guards, according to the site I'm only gaining 3mm which is only the height of two stacked pennies. I know that adding 3mm clearance is better than what I currently run, but is that significant enough to make a difference?

Any input is much appreciated.

Thank you.

fietsbob

ETRTO Number 622.. A diameter .. +2x Width . simple Math.

jonc123

You said the fenders are at their highest adjustment. Did you install the fenders or did someone else? The V-Stays may have already been trimmed by someone. Planet Bike sells spare parts for fenders.

You may not be able to use longer stays if the fenders are maxed out against racks, etc.

Leebo

Custom fenders, alternative ones, plastic strips on the seat post or bottom of the rack. Pics might help us help you.

MAK

JONK and LEEBO... The front fender is flush with the bottom of the fork and the back is flush against the crossbar behind the seat so both are as high as possible. Since I still have about a quarter inch left on the stays, I'm thinking of cutting grooves in the fenders, maxing out the stays and sealing with silicone if I don't change tires.

MAK

I know what the 622 represents but the rest of the formula (if it is a formula) doesn't make sense to me. Also, if the width you're citing is the tire width, aren't most tires stated widths inflated and not accurately represented by the manufacturers?

I was hoping for information based on experience.

jonc123

Your wanting to go with bigger tires. The fenders are strong because of the way they are shaped; changing that shape by cutting them will weaken them. Have you thought about a different frame that can handle wider tires/fenders/racks?

I can insert a finger between my tires and fenders (Planet Bike), I never have problems with rocks. A few leaves get stuck and make noise.

MAK

I am also a product of the same era. So you're saying Width (37mm)= Height in radius so 2x That. 2x 37mm = 74mm which is ridiculous.


I note that you have 21,566 posts in 75 months. That's 287.56 posts a month and almost 10 a day. (Simple math) When do you have time to ride your bike?


Let's do each other a favor. Please don't respond should I post anything in the future. I find most of your comments on BF condescending and not very helpful.


I'm ending it here before the mods get involved and I won't respond should you choose to make me 21,567. Have a great Thanksgiving.

BigAura

I think what he was trying to say was:

(622mm + (37mm * 2)) = actual your outside diameter (assuming your tire is round shaped and the tire width is accurate)

Obviously FB skipped a few English classes

shelbyfv

If you can get a caliper and measure your inflated tires and also measure the inside width of your rims it would be a good start. The height as well as the measured width will vary with the width of the rim.

B. Carfree

It looks like your choices are:
1. Go to narrower tires, which will also mean higher pressures and a less comfy ride with increased rolling resistance
2. Modify the fenders to give more clearance. There's a real risk to modifying a front fender. If it folds up and locks the wheel, bad things tend to happen. This is also why you don't want to roll with inadequate clearance between the front fender and the tire.
3. Give up on the fenders. You're going to get wetter/muddier, but at least the wheels will go 'round.
4. Change to 650B wheels and make the necessary brake/frame modifications. This is a snap for disk brake bikes, but isn't really that big a deal for others. (I changed my wife's 1984 Trek 720 over from 700C to 650B last year, but she was already interested in new brakes that were going to require new posts, so the wheel size change wasn't forcing that issue.)
5. Buy a new bike that has adequate clearance for wide tires and fenders. The current trend is for much wider tires than just a few years ago, so you might consider making sure any new steed can handle things up in the 55mm range.

djb

I don't have any suggestions, but re tire height, I may be wrong but I thought that I have read that the rim width and how a tire sits on a rim can make a slight diff in how the tire shape is. Maybe look into this to see if this would make a slight diff with a given tire/rim combo.
To be honest, while I have looked at tire widths in rreal life vs what it is claimed to be, I have never looked at the height aspect.

ulitimately thats too bad that the frame limits you to probably 32s to have a reasonable tire/fender clearance, but it is what it is.
I guess you'll have to decide if using 32s is ok for you or not. If not, as mentioned, a diff frame seems to be the only real option as I don't see how you could fudge the fenders higher if they are already up against the limit of the fork etc.

shelbyfv

Someone posted this awhile back. Shows that a given tire becomes taller as well as wider with a wider rim. Was news to me!

1Mule

I note that you have 21,566 posts in 75 months. That's 287.56 posts a month and almost 10 a day. (Simple math) When do you have time to ride your bike?


Let's do each other a favor. Please don't respond should I post anything in the future. I find most of your comments on BF condescending and not very helpful.


I'm ending it here before the mods get involved and I won't respond should you choose to make me 21,567. Have a great Thanksgiving.[/QUOTE]

Boom, nailed it. And, I concur

10 Wheels

Boom, nailed it. And, I concur[/QUOTE]

I have in 60,000 miles with my high post count. 29,918 posts