Specialized Crosstrail sports disc, gearing question..

[Otto Sump]

Hi group, I recently purchased a Specialized CSD, before I bought the bike I asked the salesman if the gearing was adequate for my needs, I'd been using a Marin Bobcat 24 speed which was getting a little long in the tooth, my preference for using the cycle paths & roads had increased so I told him that I would like a bike with more gears for cruising. He assured me that having 27 gears would be all that I need. Well it isn't, I find when going down a slight hill I soon run out of gears and my legs are going ten to the dozen trying to average 25-30mph. Can anyone tell me if I can increase the size of the main gear so I can achieve a better cruise? Any advice would be gratefully appreciated.
Regards, Otto c/o Whitehaven West Cumbria
PS Great site, keep up the good work..

 

[MrJamie]

I think my Giant hybrid has the same ratio 48-11 top, but I dont find it spins out until over 40mph downhill. Im just curious as that gear to me is always really fast. http://www.machars.net/bikecalc.htm You can look at cadence at different speeds there, it suggests 700c 48-11 at 25-30mph to be 70-80rpm which i dont think is quick. On that site even if you look at a 52 front, 11 rear youre still looking at 65-75rpm for 25-30mph.

No idea about what you can/cant change it to, just suprised that youre finding it too low

 

[Otto Sump]

Crikey Mr jamie, thats very technical, not sure I understand most of it. Been out on the bike today and my little legs were going like crazy. Checked I was in the top gear, next time I'm out I'll try and count my revolutions along with my speed.
Thaank you very much for the advice, I really appreciate it..

 

[Norm]

When you say that you run out of gears, is that with the chain on the biggest ring at the front and the smallest ring at the back? I'd be amazed if you weren't able to ride over 25mph with a 48-11 set up.

 

[Otto Sump]

Thats right Norm, big cog on the front, little cog on the back, I can get up to 25-30mph but I am flat out and feel that I need another gear, my legs are going flat out.
Regards