Author Topic: MP4 freewheel and gear shifter questions  (Read 3618 times)

Offline Weenus

  • Confirmed
  • New Member
  • *
  • Posts: 2
MP4 freewheel and gear shifter questions
« on: March 08, 2015, 02:50:02 AM »
Hello,
I'm thinking of purchasing a MP4 rear wheel kit to mount on my basic 24 speed mountain bike.  I've been doing some google research but, still have some questions.

1)Can the MP4 be mounted with an 8 gear flywheel?  If the 8 gear flywheel will be a problem, is it easy enough to switch it to a 7 using the same shifters/derailleurs or do I need to switch out all of the hardware to turn it into a 21 speed bike?
2)My gear shifters and brakes are integrated (see pics)...can I use these as is or do I need to get a new set of shifters so that I can use the brakes that come with the kit?  I was thinking that I may be able to just remove the brake lever and then install the lever from the MP4 kit...wondering if anyone else has worked around this issue.

Thanks



Offline Bikemad

  • Global Moderator
  • Professor
  • PhD. Magic
  • ******
  • Posts: 5,510
Re: MP4 freewheel and gear shifter questions
« Reply #1 on: March 08, 2015, 12:09:23 PM »
Hi andto the forum.

It should be possible to mount the eight speed freewheel (not cassette) to the MP4 but you may need to add a spacer washer (or two) to the axle to give adequate clearance between the end of the freewheel and the frame, and you may need to spread the frame slightly to accommodate the wider axle (spreading and aluminium frame is not recommended as it can lead to failure of the frame).
I would go for a seven speed freewheel and some new indexed thumb shifters as I consider them to be the best option with a twist throttle.



I have some shifters similar to yours on one of my bikes and they are a real pain when used in conjunction with an electric motor. If you start off in a low gear and accelerate quickly you cannot operate the trigger action change gear quick enough to keep up with the motor's acceleration! If you are able to remove the existing lever and fit the additional GM brake lever it might be OK, but I suspect that the brake operation may be hindered by the gear levers (and vice versa).

This is my preferred set-up as I find the twist action throttle control to be more natural and easier to apply smaller throttle movements:



The lever action on the gear shifters makes it very easy to quickly go through the entire range of gears if you suddenly have to stop on a steep hill you can change down to your lowest gear in one swift action ready to pull away quickly. Once moving again you can quickly shift from your lowest gear to the highest gear in one swift action too.

Check out this thread for more information.

Alan
 
 
« Last Edit: July 02, 2017, 11:56:30 PM by Bikemad »

Offline Weenus

  • Confirmed
  • New Member
  • *
  • Posts: 2
Re: MP4 freewheel and gear shifter questions
« Reply #2 on: March 08, 2015, 04:19:40 PM »
Thanks very much Alan.  That all makes sense...I was trying to be as economical as possible but, will probably just bite the bullet and pickup some new shifters and a 7 speed freewheel like you suggest.

Would you mind confirming me as I'm sure I'll have more questions once I get my kit and start working on it?

Steve

Offline Bikemad

  • Global Moderator
  • Professor
  • PhD. Magic
  • ******
  • Posts: 5,510
Re: MP4 freewheel and gear shifter questions
« Reply #3 on: March 08, 2015, 06:11:00 PM »
Steve, I had already confirmed your account before posting the reply to your initial post.

When you get your bike on the road you will soon realise why all those gears are not required. The most important gear will be your top gear, as this is the gear you will probably use most of the time, and its gear ratio should also be as high as possible to give your legs a chance of keeping up with the pedals.
The biggest chainwheel you can find combined with the smallest sprocket on the rear is ideally what you should be aiming for. ;)

Alan