gear chain set upgrade, help please


New Member
Hi there, I'm new to this forum and in fact any forum so hopefully this won't sound to daft. Last year I bought a careers zelos from halfords and completed several rides bit my main one being a triathlon. At points in the race I was unable to pedal fast enough to keep up with the wheels (spinning out?). I was wondering if it is possible to change the cogs to larger ones in order to he able to go faster?
Thanks for any help received.


Chandler's Ford
It is possible, but unless you change a lot of other parts you are going to lose a lot of the gears that will get you uphill.

If the wheels are going round sufficiently fast that your feet on the pedals can't keep up my suggestion is to stop pedalling. There is no shame in freewheeling and you can save that energy for later on in the race.

However you can work on your pedalling technique too.
If you've a gym near you that does spin classes give them a try. If you can comfortably spin 150 rpm - 180 rpm indoors you will be well placed to maintain a relaxed and very efficient 100 - 110 rpm in your competitive events.
If no suitable gym.... buy, or build, a fixie.


As long as I breathe, I attack.
I cant remember if the zelos has a frewheel

or same speed cassette ?

I think its the 1st , if you look at your gears the 1st screws onto the wheel,the later has a lockring holding the gears onto a hub

The front chain rings are listed as a standard 50/34 compact , im betting it has a 14-28 freewheel on it at the back>Count the number of teeth of your fastest gear at the back to see .
If it is you can get 13-25 which will make you a bit faster
You would need a freewheel tool and a spanner to change it
Or pop to a bike shop to see if they can get one in and change it for you .



As long as I breathe, I attack.
Based on sheldown browns gear calculator at 90 rpm a 50x14 gives you 25 mph , a 50 x 13 is 27 mph .
I ride a 50/36 with a 12-25 for commuting and @PpPete says learnign to spin is the way to go as i dont even use the 50x 13 or 50 x 12 till im hitting 30 mph +
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