Mainframeguy

Having got the hub and maybe the rims - I now need a drum brake! But of course all the Arais have gone, except Peter White has a stock but only if I get a wheel built in the states and shipped - making my hub redundant too.

I have asked if he would do a deal - we will see....

Meanwhile SJS over here in the UK offer something called the "Karasawa" drum for the rear hub, but I they are out of stock at the moment and I have no idea how they would compare anyway....

I have now become too tired to scroogle around anymore and just thought I would use my last energies to post and see what advice may come my way from you good folk!

The sun is shining and I am hoping stoker may be up for a little riding to check out my latest adjustments and maintenance....

nfmisso

It is a Japanese company with a factory in China. Rear drum brakes are extremely common on bikes in China (small like 80mm), more so than rim brakes, though they do not appear to be up to the task that the Arai does on tandems. Karasawa seems to have several different sizes. One of the bigger ones would probably work.

https://karasawa.freeb2b.org/product-...rum_brake.html

SJS or a distributor evidently bought around 1000 sets for around $20-25 (USD) FOB China, and I would guess that they are now on the way to the UK. With all the expenses involve, 50 Pounds seems a reasonable price.

Going home tomorrow, currently in Chang'an, Dongguan, China.

Mainframeguy

Many thanks for that - given the nature of application for us it sounds like this is going to be the way to go.... and another forum member has offered a wheel set that gives me rims so with those two parts in place I shall have the ingredients of a wheel build, it won't be in time for our week in France this summer, but maybe for the tail end of the season... Think I shall place order with SJS when they get back.

Oh by the way, for anyone else turning up this thread, I heard back from Peter White and his stocks are exhausted (but website obviously out of date).

So thanks again and safe travels too.

Chris_W

Thanks for doing all the research on this. I've given up on our rear cable disc brake due to having multiple problems and realizing that a drum brake is what we really need. I was therefore wondering how Arai stocks now stand, but it sounds like an Arai won't be an option. Over the past year, I believe TandemGeek (or maybe some other user on this forum) has been dropping hints that a new drum brake has been in testing, maybe that is the Karasawa that you found. The Karasawa doesn't sound ideal though, so I hope there is something better in the pipeline.

wtandem

Tandems East still shows the Arai available on-line:

https://www.tandemseast.com/parts/brakes.html

steve53mg

I would keep an eye on ebay...Arai brakes still surface from time to time.

deanack

I have a used one in my parts bin, what are they going for on Ebay? I take down the price from there, if you are interested.

Dean

Mainframeguy

well - totally unsure of Ebay valuation, a lot will depend on condition and state of pads etc... they cost for replacement and the drum can need to be refinished on a lathe even...

But I shall go out on a limb a little and offer £45 plus covering shipping (you'll have to advise since I am UK based) if that is of interest - can pay by paypal if acceptable? Unable to send a PM until post count above 50 though hence posting my offer in public

My offer is made from a pragmatic point of view that the Karasawa can be had for £50 here in the UK from SJS cycles....

PS My partner just pointed out that customs COULD exercise a tax on this, so I would need to look into that before making a definite commitment, since money is a bit tight here....

Mainframeguy

OK, going to answer my own question here and offer up this link which just popped up on Ebay - it shows that an Arai drum is being offered at about £100 and then the import tax on that is another £50, which is outside my budget I am afraid. I thought I should add the information for anyone else who turns this thread up in my position, or similar. I have put an advance order in for the Chinese drum and maybe I'll post back when they come in and I have completed the wheel build and actually get to try this out in anger (likely not this year though!).

chichi

What has caused you to give up? I realize you are riding some significant descents which push the brakes to there limits.

We are a 330-340lb team plus the bike and ride the hill in the San Francisco Bay area regularly, our rear brake is a modified Aavid BB7 with a hope vented disc it has been working quite well. We have also done some credit card touring with it. I am however keeping my eyes on the cyclocross hydraulic disc market as I think theere may be some oppotunites to use that technology on a tandem.

Chris_W

I took the Avid BB7 off of the rear of our tandem recently for several reasons.

The two more permanent problems were interference with the rear rack (unfortunately, the mounting tabs are on the seat stay and not the chain stay), and not being able to keep the 203mm rotor true enough to not touch one of the brake pads at some point in it's revolution when the pads were set close enough to have decent stopping power.

Lately, I decided to move control of the disc from a lever on the stoker's bars to the captains RH lever, and give the stoker control of the rear V-brake instead. We have the mountain version of the BB7, so I had to add a travel agent to do this, which was working OK, but the lever didn't have the feel that I was hoping for. Then I switched from Shimano STI levers to Campy Ergo levers due to rear derailleur adjustment issues. With the Campys I discovered what other people have reported here, that I needed to add an extra spring in the cable run in the Avid BB7 to give it enough pressure to open again after use (the return spring in the Shimano levers is a lot stronger than that in the Campys). It took a while to find a place to buy the right size and strength spring, and until then it was barely working. Just when I thought I had solved all the problems, the brake just stopped closing properly and I couldn't figure out why. I was ready to give up on the brake by then, so I took it off. I put it on my flat-bar commuter and it's working perfectly.

Just after removing the disc, we did a one-week camping tour around Brittany without it. There were no long descents, but some short and steep ones, and the two rim brakes were completely sufficient, so I was hoping that I could get away with not having the disc anymore. However, after returning to Switzerland we've done some more serious Alpine descents and have had problems with tubes popping during descents; I believe this has been due to rim heat, although the tires have never popped off. I'm therefore now trying to figure out what solution to go with - a road BB7 controlled by the captain, or by the stoker, or a drum brake. Or I'm thinking that some problems will be solved by having a shorter cable run to the disc brake, and so I have thought about getting a disc compatible fork and front wheel and using a disc there instead (this solution would also solve th rack interference issues). As I said, I cannot decide what to do, but I certainly need to improve our braking capacity and power in some way.

Carbonfiberboy 

I bought an Arai drum off ebay and love it. We only run that wheel in the mountains. When I'm running a used bike that cost $3K (half price!), have another couple thousand in spares and clothes, and the second base wheel cost me ~$400, paying $250 for the brake seemed like a great deal. Our bike came with a pac-man for the brake, but not a braze-on for a disc. A tandem really needs 2 sets of wheels, anyway.

I've had a hot tube pop on the inside because of a poly rim strip, but otherwise never heard of that without a blow-off. Hasn't happened with Velox tape.

Mainframeguy

The drum arrived yesterday

SO far I have hub, drum - and a member on the forum has mentioned a couple of Rhyno rims which I want to collect (if you see this post please PM email or addie)....

Watch this space since I intend to open a fresh thread to report my experiences once the wheel build is underway!

I'm pretty darned excited!


Interested to explore this further, by PM if possible since our riding weight comes close, but is scheduled to drop to sub 300 or at least close on order that we take on a particular century+ ride..... It's complicated by the fact we do NOT have terrain that challenges us so greatly and I shall make another thread once I get experienced enough....

Chris_W

We're going on a 5-week long tandem tour of New Zealand soon, and I'd really like to get our braking situation sorted out beforehand. Total weight, including riders, bike, and panniers is probably going to be 400-440 lbs (180-200 kg).

The Karasawa looks like a decent option in terms of it being readily available for a decent price (in contrast to the Arai, which is not readily available, and is much more expensive when it is). However, I've been unable to find any user reports of the Karasawa to know whether it is effective. Therefore, I'm hoping that mainframeguy or someone else can help to answer a few questions:

How well does it handle heat build-up on extended steep descents (e.g., 5+km at 8-10% with up to 200kg on board)?
Is it easy to mount, and more importantly, can it be easily dismounted in the field to allow spoke replacements when necessary?
Is all the hardware inside the frame (or below the chain stay) so that it won't cause any rear rack interference?
Would a bar-end shifter be an effective way to control the brake?

Thanks for any info.

ksisler

I think the installation manual is a PDF downloadable to help answer the basic questions posed. The K brake is basically a form/fit replacement for the Arai so the info on Sheldon's site for the Arai would seem to be a good add to whatever the user manual offers... Overall the new brake looks smaller and more compact that the old mule. The site that sells the new one also carries the kits for the Arai (pads, mounts, disconnect cables, etc.). Whether the new one is good or really good, I don't know from first hand knowledge.

Chris_W

Can you give a link to the installation PDF that you mentioned - I cannot see it anywhere on the SJS page (here) or the manufacturer's site (this is the model that seems most similar, but there are several that it could be). On Sheldon's site, I only found the Arai mentioned as part of the tandem brakes page (here), but there is nothing very specific. I did find a pdf on installation and removal of the Arai on Santana's website here, which is helpful.

I'm still worried about removing either brand of drum brake in the field if a spoke brakes - can anyone give first-hand experience of actually being able to do this?

Our Avid BB7 Road 203 mm brake is currently working quite well in terms of short-term braking power; however it still suffers from three inherent problems that going to a drum brake could solve: 1) Interference with the rear rack, 2) Regular truing is required to keep the rotor from rubbing/zinging, 3) It has a smaller amount of heat capacity than a drum brake. This is why I'm considering a drum brake, but if it introduces further potential problems like not being able to replace spokes, and if the heat capacity of the Karasawa is not much more than a 203mm rotor then I might not bother changing anything.

Carbonfiberboy 

During our recent loaded tour with V-brakes plus an Arai, I noticed particularly:
Descending steep and rough roads where it was impossible to let the bike run, the drum improved my control over the bike. It felt safer, especially to Stoker.
The drum really saved on rim wear. I used it even when it wasn't necessary.
It's a wonderful parking brake. I took to using it when we were just stopped. Frees up the captain's hands.
There were at least a couple of descents where it would have been dicey with just the rims.

I have it on a Shimano bar end lever on the right side of the captain's bars.

It's hard to pedal if I forgot and left it on.

We carry FiberFix spokes. I think it would be impossible to remove in the field, but then so's the cassette.

Chris_W

Removing the cassette while on tour is no problem because I have a Hypercracker tool. I'd guess that the tool is only about 100 grams (edit: only about 40 grams in fact) and it doubles as a spoke wrench; see info here, as well as info on many other similar solutions. I just tried it out a couple of days ago on the tandem and although it is fiddly and awkward to use, it's more than capable of removing and replacing the cassette.

I also carry a FiberFix spoke (and I even got to use it once, but that was on a friend's single bike). Unfortunately, the FiberFix is only intended to be a temporary solution even on a single bike - I wouldn't want to have to use one for long on a tandem. I'm thinking that not being able to remove a drum brake to replace spokes is going to be the deal killer for me with any drum brake.

I'm now seriously thinking about keeping the Avid BB7 and replacing the stock 203mm disc with a Formula 220 mm disc and getting the corresponding brake mount. This may be able to improve all 3 of our problems with the current disc - it will have slightly higher heat capacity (although only slightly), it will move the brake up about 10mm, relieving our rack clearance issue slightly, and the rotor's aluminum carrier may be easier to keep straight than the spindly 6 arms of the Avid rotor. At the same time, field removal of the disc is a piece of cake because I only need to carry the Torx 25 wrench that I'll have anyway for BB7 adjustments.

As for using the drum brake as a parking brake, I already have one of those - it's just a couple of strong rubber bands wrapped around the bars below the brake lever; I use them to hold the regular brake lever in place when the bike is on a train or in other imperfect parking places. I'm happy to hold the brake lever myself when stopped briefly at a traffic light.

Carbonfiberboy 

Checking your link, noting the non-existence of more Hypercrackers and the notes about possible frame or dropout damage from other tools, I think I'll stay with the FiberFix. Plenty good enough to reach a bike shop. OTOH, I've never broken a spoke on any bike. Tandems seem particularly safe if you have the 145 spacing. We true our rear wheel less on the tandem, even loaded touring, than I do on my singles, light. Might also have something to do with the Deep V rims instead of the lighter rims I run on my singles.

Afterthoughts: Are you adding the disk to your rims as an additional brake? If so, how would you actuate it? Referring to the parking brake, I meant using it while taking a standing break or clothing change. When touring, we like to mostly take water breaks while stopped, instead of drinking on the bike. We try to pick scenic spots to stop. I don't like taking a hand off the bars when touring on rough roads - or even smooth roads for that matter. I don't use the drum at traffic lights.

Mainframeguy

@ Chris_W - I think the general specification of your bike is such that, just maybe, you'd like to consider and Arai and it seems there is an option on one here, as I just read. I realise you are erring against going with a drum brake on the grounds of servicing on the tour, and at the end of the day that is your decision. If you have a budget though - do consider trying it with a wheel build for the hub brake, since you can always then swap back the old wheel if you feel it might suffer a broken spoke or you do not perceive the benefits of the hub sufficient.

Just a thought, if I remember rightly your bike is pretty high specification and to then add a Karasawa when an Arai is available might be a shame?

ct-vt-trekker

I can recommend Briwasson as an honest seller too. I purchased a carbon fork from him a couple of years ago. He was easy to deal with and his packing and shipping were also excellent.

dstke

Just some quick feedback on the Arai drum brake. My wife and I did a tour around the alps this summer and blew through four tubes, three times on steep descents and once after we had stopped. We have an Arai drum brake and were using it on these descents. All of the blow-outs occurred either coming into or out of switchbacks. Fortunately, in braking hard we were also going slow enough to make controlled stops.

We have a Co-Motion Speedster with Avid Single Digit Sevens and went through two sets of brake pads. We were towing a BOB trailer with about 40lbs of stuff and we weigh around 310lbs combined. I'm thinking now of adding disc brakes, perhaps only on the front which would require a new fork with disc mounts.

Chris_W

FOUR heat-related blow-outs in one trip: WOW! With an Aria drum brake: double WOW! I want people to know that this is not so typical.

We live in Switzerland, and have been riding our Co-Motion Speedster in the Swiss, French, and Italian Alps for four years, including on some of the steepest, longest, twistiest descents around. Often unladen (team weight is 280-300 lbs), but sometimes with full camping and touring gear (maybe 50 lbs of gear). In all that time, we've had ONE puncture that was definitely heat-related (front wheel, part-way down a serious Alpine pass, but on a straight section, so luckily we were able to bring the bike to a stop safely), and one other puncture that I believe was caused by heat, but I'm not certain (this one was in the city, again front wheel, but it was when we had already slowed down and so was easy to control). This is in probably 10-15,000 km (6-9,000 miles) of riding and more mountain passes than I could count or remember.

Braking setup is two Avid SD7 rim V-brakes plus an Avid BB7 rear disc (203mm). The stoker controls one of the rear brakes, which was originally the disc brake, but is now the rear rim brake. We've also done some (admittedly less extreme) riding without the disc when we were having some problems with it.

Admittedly, we're both pretty experienced and confident descenders, so don't ride the brakes that much and let the bike run as much as possible between the corners. Sitting bolt upright, with knees and elbows sticking out really helps as a fourth, air brake.

Having said all that, based on our experiences of riding Alpine roads on the tandem and single bikes, there are certain roads that we will NOT take the tandem to, and would instead use the single bikes purely because the descents are too tricky on a tandem. These would include Grosse Scheidegg (both sides), the north side of the Nufenen, the west side of Pragel Pass, and the south side of Moosegg (we did this once on the tandem and had to stop halfway down to let the rear disc cool off after it faded quite significantly). If your four punctures were on those four roads, then I would not be that surprised. For comparison with roads other people might know, we've done the Alpe d'Huez descent on the tandem before and wouldn't hesitate to do it again - that was fun (not overly steep, nice and wide, pretty straightforward between the switchbacks).

dstke

Hi Chris,

We rode the Grosse Scheidegg without problems and many others. Our blow-outs were on the Jeux-Plane, Passo Stelvio, and Fadaia. We do a lot of climbing and descending out here in Santa Cruz and have never had any problem. I'm pretty sure it was the extra weight and push from the trailer.

scycheng

What kind of tire are you using? Blowouts with proper use of an Arai should be rare if you are using wider tires and letting the drum do the bulk of the braking.