Raleigh Wayfarer and fitting a larger rear cog

[wmtlynx]

Some time ago I was advised that, to improve hill climbing, I may be better off fitting a larger cog on the rear wheel of my Raleigh Wayfarer. I'd like to know if I'll need to fit more links to the chain, or if it's a case of just swapping the cog? Also, does it matter about the number of teeth? And how much difference is £5 of cog going to make going up hills? According to Bike Hike gradient data, the only hills I'm failing on are ones that are more than 10%. (Icknield Street just north of Coach & Horses at Weatheroak being my nemesis at the moment).

On another note, the back wheel has a "hop" in it, noticeable above 20mph like there's a slight flat spot in the wheel. Is this expensive to fix at LBS?

 

[RecordAceFromNew]

It seems there are two questions. The first is what is needed, and the second is what is the impact in terms of gradient tackled.

There are potentially knock-on effects on other components by increasing the size of the largest cog on the cassette. The rear mech needs to be able to handle it, and the chain might need to be longer. Whether the rear mech and chain need to be changed can be established by knowing a) number of teeth on the largest and smallest cog of the new cassette, b) number of teeth on the largest and smallest cog of the old cassette, c) number of teeth on the largest and smallest sprocket on the chainset if any, d) the precise model of the rear mech, e) the number of links on the current chain, and finally f) the distance between the axle of the chainset and the axle of the rear wheel.

The practical impact on hills is dependent and proportional to the ratio of the number of teeth on the largest new rear cog (say N) and the largest current rear cog (say O). For every turn of the pedal, you will proceed O/N feet or metre (i.e. only a fraction) as far up the road as before, but then roughly speaking a gradient of N/O times as steep as before will now require the same effort per pedal stroke, so you should be able to tackle steeper hills. Of course there is no free lunch - the penalty is that it will take N/O turns of the pedal, i.e. more turns, to go the same distance.

Hope it helps a little!

 

[Chris S]

I changed the 18 tooth rear cog on my Raleigh to a 22 tooth one. You don't need to remove a link in the chain, the frame has horizontal drop outs so you can just slide the wheel forward a bit. Remember to check/readjust the rear brake afterwards though.

When I first got my Raleigh I struggled to get up the last part of Hill Street (by the Post Office) in Birmingham city centre. It was no problem with the 22 tooth cog on the back. I later worked out that it had reduced the gearing by about 20%.


PS - RecordAceFromNew, the Raleigh Wayfarer has a Sturmey Archer 3-speed hub.


PPS - wmtlynx, I think my 22 tooth cog cost £3.50 (inc P&P) from ebay.

 

[RecordAceFromNew]

PS - RecordAceFromNew, the Raleigh Wayfarer has a Sturmey Archer 3-speed hub.

Ooops!

 

[wmtlynx]

I've now counted the teeth on the rear wheel and there appears to be 19 teeth on it. What would be the best upgrade?

 

[Chris S]

If you want to go up hill easier get as big a rear sprocket as possible. I've been told that 24-tooth sprockets exist but I've never actually seen one.

22-tooth cogs are readily available on ebay. I've got one on my bike, it lets me get up most urban hills without any problem and still gives a decent top speed. (I'm assuming that you've also got a 48 tooth front cog)

 

[wmtlynx]

If you want to go up hill easier get as big a rear sprocket as possible. I've been told that 24-tooth sprockets exist but I've never actually seen one.

22-tooth cogs are readily available on ebay. I've got one on my bike, it lets me get up most urban hills without any problem and still gives a decent top speed. (I'm assuming that you've also got a 48 tooth front cog)

Thanks Chris S. I'll get a 22-tooth one with the proceeds of the Asda bike that is currently for sale. My cycling budget is somewhat limited at the moment, so have to sell things if I'm to invest in pimping the Wayfarer.

 

[tyred]

My understanding is that the 24 tooth sprocket is actually for the Sram hubs but will fit a Sturmey. I believe SA didn't recommend anything bigger that a 22 to avoid over loading the hub. 22 does me fine but I would happily risk a 24 if I felt the need.

You may possibly need a new chain depending on how much adjustment you have left in the drop outs (each additional tooth pulls the axle 1/8" further forward) and how worn you current chain is. If it's really worn, it may not mesh with a new sprocket. The normal thing to do with the chain on a 3 speed bike is to run it until it is well and truely f***ed as a sprocket is just as cheap as replacing the chain.

 

[mickle]

My understanding is that the 24 tooth sprocket is actually for the Sram hubs but will fit a Sturmey. I believe SA didn't recommend anything bigger that a 22 to avoid over loading the hub. 22 does me fine but I would happily risk a 24 if I felt the need.

A 22t in and of itself willn't overload the hub - it's the ratio of the sprocket to chainring which will. I remember mountain bikers experimenting with triple chainsets mated to 3spd hubs. It was the granny gear which demolished the internals - not the big ring.

Is this a new Wayfarer? Have they resurrected the name?

A flat spot is almost always impossible to repair. Some can be eased out by loosening off all the spokes and battering the flat out with a blunt object - but success cannot be guaranteed. If it's a relatively inexpensive bike it's probably more cost effective to buy a new wheel.

Flat spots are caused by hitting an object too hard - kerb, pothole or debris on the road. Several factors can have a bearing on how 'flat spot resistant' your rims are:

The quality of the rims - cheap rims bend easily
Spoke tension - tight spokes support the rim, loose spokes don't.
Tyre size - big tyres have more cush and offer more protection.

But the biggest killer of rims is low air pressure, expensive rims, tight spokes and big tyres wont protect from dents if your tyres are flat.

 

[wmtlynx]

Have fitted a larger rear cog to the beast now, and hill climbing seems a lot easier now. I've also fitted some narrower tyres to it as the ones on it had some cracks in. These narrower tyres also take a higher pressure (85 instead of 55) and the bike now feels completely different - requires very little effort now :-)

 

[Chris S]

Glad to hear it worked out. I prefer my 3-speed to my MTB, the only reason I've still got the MTB is because the wider tyres are better off-road.