I'm toying with the idea of converting my old "sports bike", now about 20 years old, to fixed rather than just throwing it away. The rear spacing is 120mm and it has horizontal dropouts, both of which are ideal. However, the chainset has a 52T ring swaged on and only the 42T ring can be unbolted and removed. The neatest solution would be to remove the 42T ring, but then I'd need the largest available 22T sprocket on the back for a reasonable 63" gear (it has 27" wheels). Are there any disadvantages with running relatively large chainrings, apart from a bit of added weight?
I'm toying with the idea of converting my old "sports bike", now about 20 years old, to fixed rather than just throwing it away. The rear spacing is 120mm and it has horizontal dropouts, both of which are ideal. However, the chainset has a 52T ring swaged on and only the 42T ring can be unbolted and removed. The neatest solution would be to remove the 42T ring, but then I'd need the largest available 22T sprocket on the back for a reasonable 63" gear (it has 27" wheels). Are there any disadvantages with running relatively large chainrings, apart from a bit of added weight?
It can actually be better and give a smoother ride as the chain has less 'bend' to make and I have always found there is less chance of the chain coming off.
Also I think big chainrings look cool ;-)
John B (who owns a 68T chainring that has occasionally been used for a fixie)
"JohnB" <[email hidden]> wrote in message "]news:[email hidden]...
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Zog The Undeniable said:
I'm toying with the idea of converting my old "sports
bike", now about
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20 years old, to fixed rather than just throwing it
away. The rear
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spacing is 120mm and it has horizontal dropouts, both of
which are
Quoted message said:
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ideal. However, the chainset has a 52T ring swaged on
and only the 42T
Quoted message said:
Quoted message said:
ring can be unbolted and removed. The neatest solution
would be to
Quoted message said:
Quoted message said:
remove the 42T ring, but then I'd need the largest
available 22T
Quoted message said:
Quoted message said:
sprocket on the back for a reasonable 63" gear (it has
27" wheels). Are
Quoted message said:
Quoted message said:
there any disadvantages with running relatively large
chainrings, apart
Quoted message said:
Quoted message said:
from a bit of added weight?
It can actually be better and give a smoother ride as the
chain has less
Quoted message said:
'bend' to make and I have always found there is less
chance of the chain
Quoted message said:
coming off.
Also I think big chainrings look cool ;-)
John B (who owns a 68T chainring that has occasionally been used
for a fixie)
Quoted message said:
It seems obvious to me that large cogs (fore and aft) would be liable to less wear and so longer life albeit at cost of more weight (marginal consideration). For instance 50% larger cogs means that per mile each tooth is tooth is used 33% less. The chain is flexed less and the extra link or two also reduces the number of chain turns per mile. I have currently 49/21 and 46/20 fixed bikes. Unfortunately as the "20" has 4 missing teeth at the last count it is overdue for replacement. However you may well find (like me) that a large fixed cog is hard to find:- LBS1 = 15 is largest LBS2 what is a fixed cog? LBS3 = 16 is largest distant dealer catalogue says 13-16 = £10, 17-20 = £17.50 So, once again we are n the hands of the dealers/makers when it comes to choosing what WE want.
It seems obvious to me that large cogs (fore and aft) would be liable to less wear and so longer life albeit at cost of more weight (marginal consideration). For instance 50% larger cogs means that per mile each tooth is tooth is used 33% less.
Err... no:
IF you have the same gear ratio, for each mile traveled the chainrings go round the same number of times.
The tension on the chain, and so the load on the teeth would be 50% less.
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The chain is flexed less and the extra link or two also reduces the number of chain turns per mile.
However you may well find (like me) that a large fixed cog is hard to find:- LBS1 = 15 is largest LBS2 what is a fixed cog? LBS3 = 16 is largest distant dealer catalogue says 13-16 = £10, 17-20 = £17.50
St John Street list 1/8 sprockets in sizes 13-22 and 3/32 sprockets in 12-22.
