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-   -   R20 brake + wheel upgrade (http://www.bikeforums.net/folding-bikes/535087-r20-brake-wheel-upgrade.html)

rossmcloch 04-26-09 01:36 PM

R20 brake + wheel upgrade
 
Hi,

I'm looking to upgrade the wheels on my R20. At the same time this will likely mean upgrading the brakes. I currently have Altenburger caliper brakes (I'm assuming this is stock). I'm trying to decide between 406 and 451 wheels. Ive heard that with 451 wheels you can use a standard brake caliper vs having to use a long reach style. Is this correct? I plan on keeping the fenders so I will need a caliper to fit around them.

If I need long reach style calipers what size or model have people used. I heard tektro long reach calipers will fit but I could not find the exact model or length.

Is there a large benefit to upgrading the old brakes? Mine currently dont really work but I'm pretty sure I could get them going with a bit of effort.

Is the only benefit of using 406 wheels the greater availability of tires?

Thanks for the help.

LittlePixel 04-26-09 04:58 PM

yes - running 451s will give you a far bigger choice in brake calipers, but a smaller choice in rims and tyres. The reason is that the r20 was designed in the UK, where (at the time) 451s were the prevalent size for utility bikes; upon exporting them to the americas the smaller 406 size was adopted - presumably for reasons of tyre availability in those markets, Raleigh made no changes to the jigs on which the frames were made, meaning that long reach calipers needed to be used for the blocks to stretch the extra 25mm to the braking surface of the rims.

The good thing is you can upgrade the bike to proper UK spec and fit some nice solid aero road rims into the bargain.

There is definitely a benfit to upgrading the brakes. The blocks will be terrible on your alloy rims so the least you can do is upgrade those, but in all seriousness - in the time since the bike was designed and now there's been a lot of innovation in brakes and you should be able to fit a nice modern set of dual pivot caliper brakes that offer seriously better braking than the stock ones. As for blocks - most people here in the folding forums are pretty much sold on Koolstop Salmon brake pads as the best brakes for diminutive wheels.

rossmcloch 04-26-09 07:09 PM

Quote:

Originally Posted by LittlePixel (Post 8804250)
yes - running 451s will give you a far bigger choice in brake calipers, but a smaller choice in rims and tyres. The reason is that the r20 was designed in the UK, where (at the time) 451s were the prevalent size for utility bikes; upon exporting them to the americas the smaller 406 size was adopted - presumably for reasons of tyre availability in those markets, Raleigh made no changes to the jigs on which the frames were made, meaning that long reach calipers needed to be used for the blocks to stretch the extra 25mm to the braking surface of the rims.

The good thing is you can upgrade the bike to proper UK spec and fit some nice solid aero road rims into the bargain.

There is definitely a benfit to upgrading the brakes. The blocks will be terrible on your alloy rims so the least you can do is upgrade those, but in all seriousness - in the time since the bike was designed and now there's been a lot of innovation in brakes and you should be able to fit a nice modern set of dual pivot caliper brakes that offer seriously better braking than the stock ones. As for blocks - most people here in the folding forums are pretty much sold on Koolstop Salmon brake pads as the best brakes for diminutive wheels.

With 451mm wheels, do I need to take the fenders into consideration when choosing the calipers? Perhaps I am just used to road bike calipers, but it seems like most calipers would not be wide enough to stretch around the bulky raleigh fenders.

I was looking at a couple websites and most of them do not seem include sizes for calipers implying that brakes are just a standard size. Is this correct?

I appreciate your help.

Gotte 04-27-09 03:23 AM

So does that mean if I get an R20 in the UK, where I live, it will most likely have 451s? Did they keep this standard for home and only change to 406 for the US, or did they change to 406 for everyone?

Also, is this the same for all the other makes that are of similar design, such as Dawes etc?

LittlePixel 04-27-09 04:12 AM

Quote:

Originally Posted by rossmcloch (Post 8805020)
With 451mm wheels, do I need to take the fenders into consideration when choosing the calipers? .

Short answer: Yes; especially if you are keeping the stock ones. If you are getting newer lightweight fenders (mudguards) then you might be able to fit them with some good calipers. There must be different sizes as not all bikes with caliper brakes are road machines - there must be calipers for tourers where the use of fenders is pretty much guaranteed.

Can anyone help? An alternative could be to file some slots in the fenders so that smaller calipers should fit, but it's a bit of a hack. Go talk to someone at a local bike shop that should be able to help. Or ask about brakes in the touring subforums...

LittlePixel 04-27-09 04:18 AM

Quote:

Originally Posted by Gotte (Post 8806699)
So does that mean if I get an R20 in the UK, where I live, it will most likely have 451s?

I would say that's 99% definite, unless you run into one that's been to the US / Canada and back in it's life.

Quote:

Originally Posted by Gotte (Post 8806699)
Also, is this the same for all the other makes that are of similar design, such as Dawes etc?

I think the Dawes Kingpin of the same era is also a 451 frame; later bikes from the late seventies and 80s (when they ditched the 20 frame and adopted the more generic 'U' shaped european frames) seem to mostly be 406 sized - so it's really just the Twenty (and derivatives), the Kingpin and lesser known bikes (Puch, Pashley etc) that used the 451 size.

If you get a UK twenty, it's pretty hard to upgrade the rims, as the only rims you will likely be able to find domestically will be more steel chrome ones. If you want to upgrade without downsizing to 406 [and not have to get extended brake calipers / rebrazing your brake bridges] then you'd best find a good recumbent dealer (who sometimes do deal in nice modern alloy 451s) or bite the bullet and get a pair from overseas (ie US or from a Velocity rims dealer in Australia)


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