about drum brakes on a tandem

[ugo.santalucia]

I just bought a vintage Sun Wasp Reynolds 531 tandem frame for 40 quid, but it is meant to be fitted with drum brakes. I can drill the fork to take a front caliper, but the rear has to be a drum brake, I fear...
I did a bit of reading about drums... are they really that bad as Sheldon Brown says? I mean, this is not a bike to come down the Galibier and 1/4 a mile at 8% is probably as much downhill as it will ever see... we might use it to do a few vintage bike events on the flat/mildly rolling side, but nothing extreme. Not looking for a full on period restoration, just something tasteful that works and at a budget.

Also, anyone has any experience with Shimano Nexus roller brakes? Are they better than normal drums? And are the basic 45 and 55 models just as good as the premium Nexus 80 ones?

Lots of questions...

 

[firedfromthecircus]

Drum brakes can be fettled to work better, and somewhere on the internet there is instructions on how to do this. It just escapes me right now where that info is!

The drum and roller brake experts on this forum are Geoff Apps and GrahamJohnWallace. You might be lucky and they spot this thread, or you could perhaps pm them. It would also be worth your while looking up the Cleland pages here and here as I think there is information there to be gleaned. Also look up Dave Wrath Sharman as he had some ideas about drum brakes and helped develop a superior design IIRC.

 

[ugo.santalucia]

Thanks, expert advice is exactly what is needed here... together with the 90 piece drill bit set I just ordered...

 

[half cog]

Re:

Put a pair of drum brakes onto a marin mtb pre disk brake days.Removed them fairly quickly.I dont know how well they can be sorted but my experience was they are very very poor.We ride tandem more often than solo bikes now and there is no way I would run them on a tandem.To be fair we are in the yorkshire dales and so its hills most all the way and in some cases you even need the extra third brake as well as both cantis.Can you not fit canti bosses? I think a decent pair of cantilever brakes is about the absolute minimum for a safe tandem. Also the drum brakes added a whole lot of weight to the bike. You can get a whole lot of speed up on a descending tandem.Add the weight of two people and a heavy bike and you need to be able to generate a great deal of braking power in an emergency.

 

[dyna-ti]

As i understand it they looked into drum brakes on mtb's before they(industry) settled on miniaturized versions of motorbike brakes :?
Apparently they found them too powerful.

Shimano had some bumpff on this im sure :? Somebody provide a link, im too lazy.

 

[ugo.santalucia]

Re:

OK...

I have drilled the fork and the rear bridge... luckily the bridge was big enough to drill an 8 mm hole on the outside... (you have to drill from the outside, so only the outside hole can be bigger than the inside and not viceversa) basically I will fit a recessed bolt and the caliper the other way round, I have done it before and it works fine, as long as you remember to swap the brake pads...
Clearance with a 700 c rim is 63 mm, so good for long drop calipers and I can even fit 32 mm tyres.

I need to source a Chater-Lea bottom bracket sleeve to turn the 1.45 inch shell into a 1.37. The front is fine, I have an eccentric that has a bore threaded for standard BS 68 mm.

Sourced a sleeve to fit a standard 22.2 mm quill, as the hole was for a 1 inch quill, which I wouldn't know where to find.

Rear stays are spaced at 128 mm, might leave them like that and file off a washer in a Tiagra hub to respace it.

Headset serviced, seems fine. Just need to sort the gears, was thinking of single speed to start (spacers + sprocket on a Shimano freehub) and then see if we need gears

 

[firedfromthecircus]

Re: Re:

Sourced a sleeve to fit a standard 22.2 mm quill, as the hole was for a 1 inch quill, which I wouldn't know where to find.

Funnily enough.........viewtopic.php?f=1&t=325822

Only other thing to say is where are the pics?

 

[GrahamJohnWallace]

Also, anyone has any experience with Shimano Nexus roller brakes? Are they better than normal drums? And are the basic 45 and 55 models just as good as the premium Nexus 80 ones?

Lots of questions...

Drum brakes range in quality from the utterly useless to powerful brakes with the best modulation characteristics you will find on a bicycle. However, one characteristic they all share is that they are heavier than disc brakes however they require much less maintenance.

Nexus Inter-M Rollerbrakes are currently the best available drum brakes but models vary greatly in bath stopping power and heat dissipation efficiency. Basically the higher the number the better they are, right up to the massive BR-IM81 with its 90mm drum and 180mm finned cooling disk. This is good enough to slow a fully laden tandem all the way down an alpine pass, yet progressive enough to not lock lock up unexpectedly on slippy roads. It's also utterly silent and weighs a ton at 826 grams.

Sheldon Brown says "no Rollerbrake is suitable for use as a drag brake on a cargo bike or tandem. There have been reports of grease's catching on fire during long descents! Overheating to this degree will require replacement of the brake, and rebuilding of the adjacent hub bearing". Rollerbrakes use a special high temperature grease that should not catch fire. If they make any noise however then they however need re-greasing, which is a simple operation and can be carried out at the roadside if needed. Failure to to keep them well greased, could in extreme circumstances, lead to the problems that Sheldon refers to.

For your purposes the smaller and lighter BR-IM55 or BR-IM70 should suffice.

I hope this helps,
Graham.