Thursday, 9 September 2010

Hopper Wheels (pt 3)

Wheels and tyre sizes can be a bit of a nightmare. Personally from messing with bikes for a while, I know more than is healthy about the sizes that are available and what fits what. But it’s easy to forget that other people out there won’t have a clue that a 26” mountain bike wheel will be ISO 559 whilst that’s completely different from the 26” wheel on someone else’s Raleigh 3 speed. They are both called 26” but are not interchangeable at all. 

It’s the same scenario when it comes to BMX wheels. So it’s a potential mine field when you are trying to build up a wheel from scratch that doesn’t fit into the usual norms. This is compounded a bit when you want to try and save money wherever possible. For example when searching for suitable rims for the Hopper on ebay, almost every seller just describes their listing as a 20” rim without specifying whether it is ISO 406mm or 451mm & some can’t even be bother to tell you the number of spoke holes!. Equally, most of them won’t be much help when you email to ask what type of 20” wheel it actually is. It’s also a bit worrying when you email a seller who claims to be a DT swiss qualified wheelbuilder, but he thinks you’re speaking goobledigook when you ask what the Effective Rim Diameter is.

The much larger range of tyres available in 406 is the reason I decided to [reluctantly] abandon the Hopper's original size of 451 and I’ve now got a nice barely used set of Schwalbe Marathons in 406 x 1.75  and a pair of Sun Rhynolite rims ready & waiting. These will be matched up with a Sturmey Archer front drum brake hub, some short length spokes, a rear drum braked hub of some sort (probably 3 speed Sturmey Archer).

Here's the Tyres and rims:

God knows why the seller I got these rims from couldn't tell me for sure if they were 406 -- it says so on the sticker.... and the rim tape!. Anyway, they cost £13 for the pair and are just the right thing, so everyones happy.

In the meantime, just incase it'll help out with the wheel building and just because I’m sad enough to enjoy measuring silly things - I’ve added a vernier caliper to the tool collection.


  1. Sounds like you'll have a fair bit of fun. I did a three cross 451 mm wheel with a Sturmey Drum brake for the Twenty, and some of the spoke angles were getting a bit severe at that point. It might be a good idea to do 2 cross on a 406, even though they always say 3+ cross for wheels where the braking is applied at the hub. The small size and number of spokes should easily make up for it.

    Are you on Twitter too?

  2. 2 cross will be the way to go then. I'm not worried about the strength of the wheels at all, I know from the brompton that small wheels are almost indestructable compared to 700c and 26". The quality of my workmanship is more likely to be the key....:-)

    No Twitter for me, but maybe one day.

  3. I'm more concerned about that sausage roll, and whether the wall thickness of the pastry was up to scratch to the nearest thou...

  4. I'm sorry to hear that you decided to forsake the 451mm wheelsize. Although the tyre choices are somewhat limited, they are readily available none the less. The Primo Comet is an example and not too expensive. Here's an example that I have recently fitted to a Dawes Kingpin:
    Odysee Red Racer, IRC Roadlite EX And Schwalbe Durano are others.
    Good Luck