invisiblehand

New to me. Although I'm not sure that there are many 451 ready folding bikes that can fit a 1.60" wide tire.

What is OS20 PowerBlock? | TIOGA BMX Race

prathmann

There's already enough confusion about tire sizes and it doesn't help that they go against the usual convention that decimal widths (1.25", 1.5", 1.6", etc.) are used with 406mm bead tires while fractional widths (1 1/4", 1 3/8", etc.) are used with the 451mm bead tires.

invisiblehand

At least they are calling it the "OS 20" size. But yes ... I expect more than a handful of folks following Sheldon's crib notes to get screwed.

jur

From what I understand they are saying, you need a special 451 rim for these.

invisiblehand

Oh ... I see.

Perfect. That's what we need.

ThorUSA

schwalbe has a new wider 451 in 1 3/8 ( 37 mm wide ) versus the old and trusty Duranos which are 28 mm wide ....
This tire as I understand is built around electric bikes and should be pretty darn robust while only 305 grams ... Not all that cheap, but you get what you pay for

invisiblehand

Schwalbe Shredda also comes in 20 x 1 3/8.

So what is different about OS 20 that makes it incompatible with "regular" 451 rims and tires?

jur

I nominate you to get one and see if it can go on a narrow rim.

[edit]I suspect it would work. Perhaps they are keeping in mind that tyre width is more or less matched by rim width; but I have seen some very fat tyres on quite narrow MTB rims. It might squirm around corners.

BruceMetras

The only OS20 rim I could find was the Alienation.. at a whopping 34mm width.. most 451s at 19mm or less... so the BSD is still at 451, but the big OS20 deal is a fat 451 tire on a fat 451 rim.. then build a bike around the combo to make sure it'll fit your frame and brakes .. oh, and make sure there is only one tire and rim combo for the bullet bike.. and away you go!

invisiblehand

That is quite wide.

Hah! There is a good BMX shop in Falls Church. If I had a 451 bike I might give it a try.

When I last checked, Velocity's 451 rim is the A23. There are a bunch of rando guys around here that use 42 mm wide tires on 23 mm rims.

Abu Mahendra

Just came across these. Put them on the scale at the shop, and it came up 265 grams. $20/piece.



Maxxis website does not list them. Similar tread pattern to the Schwalbe Shreddas at lower cost and weight.

Rick Imby

There also might be an issue on some bicycles where the 20 x 1 3/8" might be a little wider than the frame clearance. Not very likely but it could happen especially when many of the 20" frames are really designed for 406 wheels. I would find it very hard to believe the 1 3/8 tire will have any issue fitting a 451 rim. A 2 3/8" tire maybe but the only possible issue would be tire to frame clearance.

invisiblehand

I talked to someone who put 1.6" OS20 tires on his Pocket Llama. Disc brakes. He's pretty happy with it.

invisiblehand

Is it actually 37 mm wide? A casual measuring of a few 20 x 1 3/8 tires is that they tend to measure 32-34 mm.

BassNotBass

I have Schwalbe Fat Franks in 26 X 2.35 on thin 26mm and wider 2" rims and the tires feel pretty similar. You would think that the thinner rims would make the tires feel squirrelly like they were going to roll off of the rim but they feel secure. Then again they are rated to 60 psi and I usually run them above 45 psi.

Abu Mahendra

They are about 33mm wide, and 27mm tall. IME no tire is ever as wide as its nominal rating. Ran them at 50/70psi (i weigh about 75kg), and feel real smooth, and more stable due to the wider, more square profile. Like them, and will pick up another set. Only 35 grams heavier than 35-406 Kojaks. Hope they hold up over the long haul. Have now divested myself of all 23-451 tires.

jur

Those are nice. I looked but could only find them at $46 each. Their disadvantage is that you can't remove the wheel without deflating the tyre; at least that's the situation on my Ti Swift with 1-3/8.

Abu Mahendra

...and managed to shoe-horn them on the Sunny. Running 50/70psi.