Brake lock pin adjustment
 

I picked up a used tricycle (Babboe Big) and took it to the LBS to adjust the brakes. It brakes well now. However, it is supposed to have a locking pin on the double brake lever for the front wheels. Kind of like a parking brake. The pin does not hold the brake tight enough and so it still rolls. See pictures locked vs when brakes fully engaged by hand. LBS mechanic was stumped. It has Sturmey Archer drum brakes and the original Sturmey Archer housing; the lever is unbranded.

Edited to add: The mechanic tried adjusting the tension to meet the pin but it quickly became too tight to ride (i.e. brakes dragging).

Any idea how to fix this? Or where to find a replacement lever if necessary?

Thanks!!

https://cimg5.ibsrv.net/gimg/bikefor...ca3c75295c.jpg
Wheels don't move when the lever is pulled.
https://cimg9.ibsrv.net/gimg/bikefor...eca1ba2dd9.jpg
Locking pin is engaged but brake line is not tight enough to stop the wheels.

Does the pin have a cam shape so that you can rotate it to adjust the position of the lever? I'm looking at the knurled head which usually is there for grip to turn the head. If all else fails just hold the lever closed with a velcro or ?? strap to hold the brake on and wrap it around your handlebar when not used.

I suspect those levers were never intended to be compatible with a hub brake. IIRC the locking pin/parking brake design came out of the freestyle world where rim brakes were the standard. So the amount of cable pull they have is intended for the long arm calipers that the 20" bike typically has.

Have you tried to use another method of holding the lever enough to lock your wheels? I've seen toe clip or velcro straps used for this. Andy

Tighten the brake, what's the big deal?

Thanks so much for your replies!
Unfortunately no, it spins loosely.

That was the LBS theory - he said he has seen them on other tricycles but with rim brakes. But it's puzzling because this is a feature of these tricycles. See 0:35 of this video from the manufacturer.

We tried that, but by the point we got the pin to hold the brake, the brake was still partially engaged when the lever was released fully.

The velcro strap kluge idea is OK I guess but disappointing since this was supposed to be a feature, and it will lower the resale value to have a broken part.

I don't believe the lever is faulty but trying to balance two brakes with a single handle may be the issue.

You may want to consider new separate locking handles for the front vs the back brake, here is a link to a Sunlite set on ebay.

https://www.ebay.com/itm/30249289915...0AAOSwZW5aAlEr

This will allow you easier set-up of the tension of the locking pin on each brake mechanism. Also the Parking pin operation should just hold the bike back from rolling away not a hard hold.

I have worked on quite a number of donated in used trikes at our shop and I have never been not able to properly adjust the "parking" pin for rim, hub or drum brakes.
https://cimg4.ibsrv.net/gimg/bikefor...ddf3802e5f.jpg

The only real concern in going to two separate levers that act on the two ft wheels is that the trike will steer towards the side that has a greater brake application. It's harder to balance your two hands, WRT lever pull strength, then to have that done by a single two cable lever.

Does the trike have a third brake on the third wheel? If so is that a rim brake? Perhaps a rim brake with a locking lever there might be a solution. Andy

if the lever allows, a bigger hole made into the lever handle might give enough clearance after adjusting the cable tension. The effect it will have on the other brake might be an issue if that one cannot be adjusted to account for the bigger hole in the lever handle.

Thanks for your ideas. Brake pulling steering is a major safety issue on this thing so the front brakes need to be aligned together. The third wheel also has a drum brake operated by hand lever. There is a spoke lock on the rear but it is not effective because all the weight is on the front when parked, so the back just slides along.

I just remembered that there was a bend in the brake line between the housing and the brake (cable bent at angle), meaning there could be some extra slack. The shop didn't think much of it but now that I think about it, if there was less pull needed to engage the brake then it might line up with the pin. I'll be able to look closer and take a picture tonight.

Andy, I got a little lost in your reply that the trike has two front wheels until I look up the OPs model.. I presumed in my initial reply (I guess I should say assumed) that it was a standard adult trike. My hat is off to you for picking up on that detail.
https://cimg5.ibsrv.net/gimg/bikefor...327fe6a7c2.jpg

Most trikes I have worked on, and I did presumed this one, was a standard adult trike with a single front wheel and two rear wheels. The only ones I know that have two front wheels are workman type trikes that have a box/basket in the front or the old Good Humor ice cream man trikes.

I have seen trikes with both a front wheel rim brake and a drum brake built into the front wheel, this might be a good scenario for a dual brake cable handle. but I think they are rare.

Most modern trikes (Schwinn Meridian and multiple models out of china) that have a rear brake is a drum mounted on the main axle or coaster type brake mounted on the mid (transitional) axle which is connected to the main rear axle by a short chain. The variations seem almost endless with 3 speed IG hub and 7 speed freewheel options. The absolutely cheapest versions only have a rim type brake on the front wheel.

See this video at about the 30 second mark to see what I'm taking about a drum mounted brake for the rear wheels..

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It is indeed two wheels in front. Here's a product photo (that is not me with the topbun/look of madness).

https://cimg7.ibsrv.net/gimg/bikefor...795addf214.jpg

Sorry to have misunderstood your model of the trike.

Not at all, I should have been clearer! These things are pretty rare in the US. I really appreciate you taking the time to think about my problem.

You've never seen "tadpole" type of trike? Thats the design most preferred by trike riders. Take a look at the recumbent sub-forum.

https://www.performercycles.com/wp-c...e-1024x768.jpg

I would dispute the "most modern trikes". In my experience, most modern trikes, other than the cheap ones you reference, are the tadpole type - two wheels in front with normal front and rear derailleur gearing and two front disc brakes, hydro or mechanical. There are versions from relatively inexpensive to carbon fiber with expensive wheels, just like other bikes. E versions with fat tires are also becoming popular.

But they have in common the tadpole design because they're much more efficient and, importantly, stable than the other kind. I rode one for a season when I was recovering from shoulder surgery. It was a decent trike, not super high end. It had two 20" wheels in front and a 700c in back. THe wheel size combinations available vary.. Each brake controlled by a lever, right and left. Braking was easy to adjust to be even or close enough through normal barrel adjusters and some minor finesse required when braking to adjust for minor pull if it occurred. To the OP issue: both brakes had a parking brake feature which locked the wheels tight, so it can be done.

This thread's miss understandings and thus, assumptions, only provide the reason to better describe what talk about. Ever heard the story about 3 blind men, each are about an elephant and describe the part they are touching. Each can't fathom the other's descriptions. Andy

Here's a picture of the ends of the brake cables. The left side has a bend. Would that be significant enough to add that much extra play at the levers? To put it another way, will new cables solve my problem?


https://cimg8.ibsrv.net/gimg/bikefor...5c6ba4c38b.jpg
Left side - bent.
https://cimg1.ibsrv.net/gimg/bikefor...1c508da76f.jpg
Right side looks fine.

Yes I have but not for the clientele we serve.

Ours is a volunteer charity shop serving the homeless and those in need, all bikes are donated in.... we service annually about 1,700 bikes the last few years, this year we are heading towards 2,000 bikes, not too many tadpoles, in fact is the 5 years since we established the shop, I cannot recall one ever coming in.

Now, if you want to donate one, I will gladly send you the shipping address and I will report back how our client likes them.

There is no reason why this setup cant work. Find another bike mechanic.

-SP

Thanks, I agree, since this is one of the most popular bikes of this style in the Netherlands. Unfortunately shops where I live have no experience. I guess I'll try the more corporate shop next and see if they can crack the case.

I would not have argued the point if you'd mentioned that. In my experience, tadpoles as I described are much more common. But I don't doubt that those trikes, at those price points serve your clients very well.