700c to 650b conversion

lylalenke
lylalenke Posts: 4
in The workshop
Hello everyone

I have a 18" frame Voodoo Marasa and would like to swap its 700cc tires to 650b ones.

Please do you guys know if it's possible and which tires would you recommend?
I have the feeling that slightly smaller tires would be more appropriate to my height (5'3ft).

Also would like to have chunkier tires, even though, in my limited experience, the current ones 40mm are not that bad.

This is the bike in case someone wants to check geometry etc:

https://www.halfords.com/cycling/bikes/hybrid-bikes/voodoo-marasa-womens-hybrid-bike-16-18-frames

Cheers

L

Comments

  • sparquin
    sparquin Posts: 69
    edited December 2019
    I can start the process by telling you that yes, it's possible because the bike has disc brakes. To figure out tyre sizes, look at what you can fit in there now. Going to 650 won't give you that much room for wider tyres.
    [Edited to add:] Bear in mind also that you'll lower your bottom bracket, which can have other consequences such as pedal strikes and changes to the bike's handling.
  • figbat
    figbat Posts: 680
    650b is 19mm smaller diameter than 700c, so on the same nominal size tyres, the BB will drop by 19mm. However you can get some height back with wider/chunkier tyres on the 650b - how much wider will be limited by the fork and frame width clearance, remembering that both will tend to taper, meaning a bit more width available for the 650b tyre.

    You could also go to a shorter crank if ground strike is an issue.
    Cube Reaction GTC Pro 29 for the lumpy stuff
    Cannondale Synapse alloy with 'guards for the winter roads
    Fuji Altamira 2.7 for the summer roads
    Trek 830 Mountain Track frame turned into a gravel bike - for anywhere & everywhere
  • lylalenke
    lylalenke Posts: 4

    Thank you sparquin and figbat

    Do you think it will be necessary to change the wheels to fit the new tyres?

    Also I don't intend at all to do it myself, I believe the LBS team should be able make these adjustments.
    sparquin said:

    I can start the process by telling you that yes, it's possible because the bike has disc brakes. To figure out tyre sizes, look at what you can fit in there now. Going to 650 won't give you that much room for wider tyres.
    [Edited to add:] Bear in mind also that you'll lower your bottom bracket, which can have other consequences such as pedal strikes and changes to the bike's handling.

    figbat said:

    650b is 19mm smaller diameter than 700c, so on the same nominal size tyres, the BB will drop by 19mm. However you can get some height back with wider/chunkier tyres on the 650b - how much wider will be limited by the fork and frame width clearance, remembering that both will tend to taper, meaning a bit more width available for the 650b tyre.

    You could also go to a shorter crank if ground strike is an issue.

  • whyamihere
    whyamihere Posts: 7,715
    You will need to change the wheels, which could be a fairly significant expense compared to the value of the bike.
  • lylalenke
    lylalenke Posts: 4
    whyamihere said:

    You will need to change the wheels, which could be a fairly significant expense compared to the value of the bike.

    I've spoken to the team in my LBS and they estimated the total cost on £270.

    I paid 320 pounds for the bike.

    Don't think I would find a bike with these gears and disc brakes for less than £500 so I'm still considering the change.
  • slowbike
    slowbike Posts: 8,498
    What are you hoping to achieve by going 650?
    The bike comes with 40mm tyres - so pretty wide unless you're really going off road ... ?
  • lylalenke
    lylalenke Posts: 4
    edited December 2019
    slowbike said:

    What are you hoping to achieve by going 650?
    The bike comes with 40mm tyres - so pretty wide unless you're really going off road ... ?

    A more comfortable ride in a less high bike, if it makes sense.
    I don't care about speed.

    However for what I have been reading changing the wheels and tyres won't help much.

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