20 inch tyres

[chillyuk]

I recently got my wife a shopper bike with 20" wheels. I wasn't too concerned about the state of the tyres as I have a brand new pair of tyres and tubes in the shed. I have just offered up the new tyres against the wheel and the new tyres seem larger even though they are both (old and new) labelled as 20".

I have vague recollections about some peculiarities with older and newer 20" tyres that 20" doesn't always mean 20". Has anyone any ideas about this?

 

[Zoiders]

If it's an actual original Raleigh twenty Raleigh UK suprisingly still sell the the off size tyres for them.

Sheldon has a table of the sizes IIRC.

 

[ufkacbln]

There is also a 451, 500A and 438!

Forget the 20" mark and look for a ERTRO number on the rim or original tyres

This will be in the format xx-yyy

The first figures (xx) are the width of the tyre from side to side when fitted (25 would be an inch wide for instance) this is not critical until you start to look at mudguard clearance.



The second (yyy) is the rim diameter and is the important one for fitting to the rim.

As you have found out this can be a massive difference almost two inches between a 406 and 451 tyre

The bad news is that depending on your diameter choice may be limited.

Most shops should be able to help you, but if you get stuck, St John Street or West Country Recumbents sell a variety of tyres across teh 20" range.

 

[tyred]

If it's an older Raleigh Twenty/Dawes Kingpin or similar British built bike, it will be 20 x 1 3/8" (37-451).

Don't buy the white walls like I did. They show up dirty thumbprints when you are fitting them.

 

[chillyuk]

Thanks for the advice and suggestions. It says on the frame "manufactured for Halfords" and there is no indication made by who for Halfords. I suspect Raleigh, but did Raleigh make badged bikes? It's academic anyway, it's a simple small wheel shopper with a Sturmey Archer 3 speed that all works OK. I will look into the tyres again presently.

 

[tyred]

My understanding is that in the 1970s, Raleigh sold bikes to Halfords badged as Phillips and various other lower end badges that Raleigh aquired over the years. Halfords also sold a cheaper small wheeler at that time which was made in the far east.

This is my original R20. Does yours look anything like it?


Small Wheel Ride - My 1971 Raleigh Twenty folder by braveheart1979, on Flickr




This uses the 451 (20 x 1 3/8") which Raleigh used on the domestic version of all these bikes. I think the ones sent to the US may have had the wider BMX size.

 

[byegad]

Try the small tyre shopping area in Westcountry Recumbents website. They stock or can get a lot of odd sizes.

 

[tyred]

There is no trouble getting the 451 or 406 sizes. SJS cycles and various Ebay sellers stock them. There are even high performance Conti tyres and puncture resistance Schwalbe tyres available in 451.

 

[chillyuk]

I have just looked at the tyres. The ones fitted on the bike are 406's and the new ones I have are 451's dammit! At least now I know what's what so that is good.

The bike is labelled Easy Rider, and although solid and in good rideable condition it is somewhat deficient in the cosmetic department. I intend to strip it soon and spray it and make it look decent. I need to find some new handlebars as the exixting ones are very rusty and beyond sensible refurbishment, and probably some brake calipers.

this is the bike in question:

 

[tyred]

That definitely is not a Raleigh but has the makings of a nice and unusual machine.

Seems to have seriously long drop brakes. I would almost be tempted to fit a set a 451 wheels and tyres as there looks to be clearance.