Help! my 'MTB' is too slow..

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  • mcnultycop
    mcnultycop Posts: 2,143
    After reading this thread I decided to actually pay attention to the cadence sensor on the bikes in the gym this morning. 120rpm was stupidly fast; OK for intervals in the gym but I wouldn't fancy trying to maintain it for any length of time at all.
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  • cycleclinic
    cycleclinic Posts: 6,865
    Maintinaing a high cadance is doable. On my road ride today the were long stretches above 100 rpm. My average was lower as when group riding you frewwheel and sometime you have to slow down for the group.

    However reoplacement chain rings can be bought. TA do them in all rings sizes for 104BCD. Also a wider tyres as already siad will increase your gear ratio. a 1.75" tyre is good comprimise.
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  • jamesg73
    jamesg73 Posts: 4
    OK, wow, thanks for all the responses!

    Firstly - yes i have a standard 68mm BB

    Regarding cadence, i'm 6'2" and weigh 83Kg so high cadences aren't efficient for my bio-metrics. I like to cruise at around 90 with shorter stints at up to 100. Anything over 100 sustained is never going to happen, so please don't push that tack, but the theory is understood - i'm just not a skinny 5'6" hard core road cyclist. Slightly lardy office worker is closer to the mark! :wink:

    So yes, i tend to top out around 25mph in a cruise - which is still faster than most people i come across on road bikes :D

    I've seen 48 & 50T front chainrings to suit 4 x 104, but that would mean keeping the same Q factor and i'd like to move that in by 15-20mm. Cheapest option though, so good suggestion!

    When i was asking about frame width, i was referring to the rear triangle lower arms at the point of intersection with the chainring line. since a 50T ring has a radius of 100mm, i was looking at the width across those lower arms at 100mm behind the BB centreline. Simple!

    I actually have a SRAM Apex White 50/34 kicking about which i managed to cobble on using some spacers so i know the combo of gearing & Q factor is what i want to get to, but it was VERY close to the frame so came off again. I also notice a bit of frame flex now, so getting a newer (and stiff) frame appeals if i can find something for the right price and right geometry...

    If only life was simple and i had a shed to store a road bike! :lol:
  • YeehaaMcgee
    YeehaaMcgee Posts: 5,740
    6'2" and 13 stone isn't exactly flabby.
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  • njee20
    njee20 Posts: 9,613
    Also a wider tyres as already siad will increase your gear ratio. a 1.75" tyre is good comprimise.

    And slow you down, slightly daft!

    2 bikes barely take up any more space than one, if you stack them together, is that really not an option?
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    How does a wider tyre increse gear ratio?

    Surely it is the effective tyre diameter
  • njee20
    njee20 Posts: 9,613
    Well yes, but on bike tyres wider = larger diameter.
  • stubs
    stubs Posts: 5,001
    Your 6' 2" weigh 13 stone and can cruise at 25mph :o Bloody hell get a road bike some lycra and join a club your wasted on the MTB section
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  • YeehaaMcgee
    YeehaaMcgee Posts: 5,740
    stubs wrote:
    Your 6' 2" weigh 13 stone and can cruise at 25mph :o Bloody hell get a road bike some lycra and join a club your wasted on the MTB section
    I'm smelling a rather strong wiff of BS.
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  • stubs
    stubs Posts: 5,001
    YeehaaMcgee wrote:
    stubs wrote:
    Your 6' 2" weigh 13 stone and can cruise at 25mph :o Bloody hell get a road bike some lycra and join a club your wasted on the MTB section
    I'm smelling a rather strong wiff of BS.

    Large steaming piles of it I reckon
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • jamesg73
    jamesg73 Posts: 4
    njee20 wrote:
    Also a wider tyres as already siad will increase your gear ratio. a 1.75" tyre is good comprimise.

    And slow you down, slightly daft!

    2 bikes barely take up any more space than one, if you stack them together, is that really not an option?

    I have to store my bike in my flat, so no space for a second bike :(

    Also, i did have 1.5 x 26 on previously, but as well as more rolling resistance they were notably heavier and you could really feel the increased inertia when accelerating.

    Ignoring the snide comments which IMO are totally uncalled for... Yes, if i did have room for a second bike i would get a nice road machine and join one of the local clubs. I was a member of a club previously before i moved home and had my road bike pinched.
  • njee20
    njee20 Posts: 9,613
    I have to store my bike in my flat, so no space for a second bike

    Yeah, but you're storing one there, and with two stacked against each other they barely take up any more space, particularly as a road bike has narrower bars, the MTB bars will still be the widest part.
  • YeehaaMcgee
    YeehaaMcgee Posts: 5,740
    'Tis true, my garage looks like the mountain bike is sleeping with it's arm around the road bike. Bless.
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