Ozonation

I have a Sam Hillborne (Rivendell) that I want to add a bit more suspension to when I'm riding on gravel or rough roads. It came with Panaracer 700X35 tires. I'm planning to swap them with Schwalbe Big Ben (700X50) tires (up to 2" wide). I've checked and to the best of my knowledge, the new tires *should* fit, minus my fenders.

I've fixed plenty of flats, but I've never tried to put different sized tires on my bike. I'm assuming that the wheels that came with the bike can take the new, larger width tires.

Is this a correct assumption, or should I be checking for some other measurements, etc.?

Thanks.

bobotech

PIctures of the areas by the fork and rear stays where the brake bridges go would be helpful in taking a guess if tires that big would fit.

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TallRider

Odds are good that this bike will fit 50cm tires, but have you checked Rivendell's documentation (if they gave you any - I couldn't find any mention of max wheel size on their website) or email them.
It takes *long* reach caliper brakes (and remember, normal road bikes use short-reach 39-49mm calipers, the next step is *standard*, and long is further than that).

If this works, you will have more suspension as you expect. You will also have a bit less effective trail off your fork. More rotating weight which will limit your accelerations but also mean your bike holds speed longer on flats (more rotating momentum stored in wheels takes longer to slow down).

dsbrantjr

Check all around your tires for potential tight spots. I have one bike where the front derailleur pivot/spring mechanism is the limiting factor for the rear tire size. And, as suggested above, call or e-mail Rivendell to be sure.

sreten

Hi,

40mm max with fenders apparently. Only issue might be chainstay clearance bigger.

rgds, sreten.

Johnny Alien

They will fit on the rims but most likely you won't get the full width. They will probably hit about 45mm or so mounted on those rims. With a Hillborne you will be fine with those tires you just may need to deflate them a bit whenever you need to take the wheel off.

FBinNY 

Here's a link to rim/tire width ratio guidelines from Schwalbe There's some wiggle room to the wide side, but be aware that wide tires on narrow rims can cause squirrely handling at lower pressures. They lack good lateral support and flex sideways much more than a more proper fit would.

Most don't notice it on dirt, but it can become obvious on pavement.

Grand Bois

What does brake reach have to do with tire size?

fietsbob

remember the Bontrager roll down of MA 40 rims to 26"? that was wide tire on narrow rim use.

got him to be owned by Trek Corp.


NB: if the rim is narrow it reduces the width of the mounted tire,
compared to mounting same tire on wider rim ..

TallRider

Not a direct indicator, but bikes designed around longer-reach brakes will be designed to make use of the full extent of the brake's reach. Grant Petersen is a huge fan of larger tires and longer-reach brakes that allow the brake bridge to be placed further away from the wheel to make room for fenders and larger tires.

Grand Bois

Rivendell Bicycle Works is my LBS of choice. Since they sell both the bike and the tires, I would be asking them. If you look at the Big Ben page, you'll see that someone put 700 X 50s on a Hillborne with canti's.

Ozonation

Thanks all. My Sam is newer, and it doesn't have cantilever brakes, but dual pivot calipers. I did contact Rivendell, and they said 700X40 (Little Ben) would be the max, as another poster indicated.

However...

... I came across a blog of a bike shop that modified a customers Sam to accept a Rolhoff, and in the photo, the Sam had the same calipers as mine and 2.0 inch wide Big Apple tires! I contacted him and he confirmed that the tires fit: it was tight, but there were no issues. Fenders, of course, had to be removed.

So, I think I'm going to go for broke, specially since 50 mm wide Big Bens on the Rivendell website were measured to be about 45 mm.

But I might check into the chain stay clearance, although I think there should be enough.

sreten

Hi,

40mm is the claimed maximum with fenders, without it will be bigger.

Dropping normal road pressures for off road will give you more grip
and suspension. "Little Ben's" come in 40mm, the choice is yours.

rgds, sreten.

Johnny Alien

Here is a photo of a Hillborne in which the Riv folks installed a 45mm Schwalbe 650B. It looks pretty darn tight but there is a little bit of room. I think a 50mm tire would be cutting it pretty close keeping in mind they are all probably inflating less than the marked size.

Ozonation

Huh... that does look a bit close. Maybe I should stick with the Little Bens.

Grand Bois

I like the brown Little Bens. I may get a set for my '59 Carlton.