Hello iv'e been looking at converting my front wheel to dic brake am only thinking about it at this stage just wanted your thoughts on it. if i do it i can easy change it back to standard hear have a look at this. also i may put 199B S/Arm on the 198A frame.

Edited April 24, 201511 yr by bondy

Well you did ask for our thoughts.

 

Sacrilege

 

Stuart.

There are better brakes then the original Bultaco but I personal wouldn't do it. Try to find a Bultaco double shaft action brake plate and mount that to the hub, this will improve braking a lot and would be contemporary.

or use an Alpina/Frontera hub

Hello no don't mind your comments i don't it them personal as i said am only thinking about it at this stage not even got that fare yet frame S/Arm still in the paint shop. i will keep you posted thanks for your thoughts bondy,

or use an Alpina/Frontera hub

hi,

i am interested in your comment for other reasons, can you tell me please why the Alpina or Frontera front brake is better than the Sherpa??  I though they were the same diameter, same shoes and same brake plate etc.  always after other peoples useful comments and experiences.

the best i have my sherpa is relined hub, by shrinking cast steel liner into it, bushing the brake pivot cam hole in the plate, having original FORMA shoes relined and then machining them back to the required diameter of 125.00mm.  from your suggestion I am wondering if I have missed something as I am fairly certain my Pursang has a Frontera front wheel but cannot see any difference!

i like my bultaco as original as possible, but not at the expense of it working as best as possible.

Hencam, I believe you & I had a discussion some time ago regarding using a 138 Alpina

rear wheel to get proper 199's rear brake.

That said Feetups comment rang a bell, so went to the shop to check on a slip up my son & I pulled

some years ago when building his M49, got a good deal on a set of Alpina wheels as the ones

we had were the older Akront rims & we liked these.

Needless to say the rear was fine, the front drum is 5.5 dia.140.omm Sherpa is 4.9 dia. 125.0mm

so no go without the proper brake plate & shoes.

I suppose we have had good luck with chrome, plenty of front brake but as I have already been

informed, different climate.

Larry

Larry, that is a beautiful bike,very nice work!

Bondy,

 

It depends on the year but the later Frontera/Alpina hubs are a bigger diameter and by definition more powerful. I have a  M166 350 Alpina and also a M215 Frontera and both have 140mm front and rear and whilst I agree are more powerful still suffer from all the same issues that the smaller Sherpa ones do.

 

On my M199 I relined the front hub with a very good quality cast iron. (had to buy a slice from a solid bar and machine out the center which  took me about 3 evenings to just produce the insert) The back plate was bushed so the pivots were perfect. I have never liked the Nurfen linnings so the shoes were relined with linings normaly used for fork lift trucks and then machined for a 100% contact fit in the drum. Result, powerful working  brakes that I can easily lock the front wheel in most sections  with one finger. Needs a bit more pull when on the road.

 

Why fit a disc brake when the originals can be made to work?

 

Stuart

Edited April 26, 201511 yr by twinnshock

hi,

i am interested in your comment for other reasons, can you tell me please why the Alpina or Frontera front brake is better than the Sherpa??  I though they were the same diameter, same shoes and same brake plate etc.  always after other peoples useful comments and experiences.

the best i have my sherpa is relined hub, by shrinking cast steel liner into it, bushing the brake pivot cam hole in the plate, having original FORMA shoes relined and then machining them back to the required diameter of 125.00mm.  from your suggestion I am wondering if I have missed something as I am fairly certain my Pursang has a Frontera front wheel but cannot see any difference!

i like my bultaco as original as possible, but not at the expense of it working as best as possible.

The Alpina/Frontera/Pursang front hub does look very similar to a Sherpa T front hub, but it has a larger diameter brake drum. The similar appearance is why I suggested it. It is hard to tell the difference visually unless both wheels are close together. I can arrange a photo showing this if you like. There is a slight weight penalty with the bigger brake drum.

I have a couple of spare front Alpina wheels and brake plates I would be willing to sell if someone wants to make this change, but I am Australia so postage to overseas would not be cheap

Edited April 26, 201511 yr by andy

Hencam, I believe you and I had a discussion some time ago regarding using a 138 Alpina

rear wheel to get proper 199's rear brake.

That said Feetups comment rang a bell, so went to the shop to check on a slip up my son and I pulled

some years ago when building his M49, got a good deal on a set of Alpina wheels as the ones

we had were the older Akront rims and we liked these.

Needless to say the rear was fine, the front drum is 5.5 dia.140.omm Sherpa is 4.9 dia. 125.0mm

so no go without the proper brake plate and shoes.

I suppose we have had good luck with chrome, plenty of front brake but as I have already been

informed, different climate.

LarryPicture0204152136_1.jpg

Hi Larry,

yes we did and your suggestion was spot on, only because a frontera wheel was so expensive i used a japanese trail bike wheel that had chain drive one side and brake plate the other.  while that was working fine (very well in fact) i set about the original Bulto wheel in the sherpa as described above.  

because Bondy was asking about front disc, my reply was more centered around that.  i was not aware the alpina/frontera fronts were 140.00mm.  i assumed (as always makes an A$$ out me) that pursang, alpina and frontera were the same front brake at 125.00mm.  i reckon somebody has fitted a sherpa wheel to my pursang!

however even the front on my sherpa works excellently with the hub lined, pivot bushed and bored and shoes with proper linings machined back to the required diameter.  i just never had a lot of luck with newfren linings.

thanks again for the previous advice.

Well that is good news, if you can post a picture of the rear setup,

that will be of help to all.(there is a thread).

Since our conversation, we sourced a 138 Alpina rear setup for the

younger competitor (only 48 or so) so he now has good rear brakes.

Larry

 

Hi Chaps, My 199b front brake chrome  drum  was in perfect condition with new shoes  fitted it worked well and would lock the front wheel if needed so all good. My only criticism was that adjusting it so it was just binding the handle bar lever had a lot of movement. Any way I had read a lot on here  about buying a aluminium front bake operating arm  to put on the clutch to increase the leverage and lighten the clutch operation (replacing the shorter steel one).

So as it was Sunday and In Motion were shut I thought I would simply swap them over putting the short steel operating arm on the front brake. Anyway  with some adjustment the clutch was much improved (I also left off the return spring from the top of the clutch lever on the crankcase) I can know use it with two fingers. But what surprised me is the front brake is now fantastic! Much shorter travel one or two finger operation and still enough leverage to lock up the front wheel if needed.

And all for free. I just had to have a ride around the block (it is road legal) now my bike rides on two finger controls.

Happy days.

Martin.    

Thanks for posting that Martin.I,m going to try that on mine after I get some new clutch plates in.

 

On my M199 I relined the front hub with a very good quality cast iron. (had to buy a slice from a solid bar and machine out the center which  took me about 3 evenings to just produce the insert)

Were did you get the cast iron from, I want a piece to do pursang drum.

 

I deal with loads of metal suppliers at work, not one can supply cast!