MZ TS250 Front Brake Upgrade!

[Pat the Jawa]

As any MZ TS rider will know - the front drum brake is barely adequate at best and almost useless at worst. I have found one upgrade on another forum which involves having the old shoes fitted with thicker brake linings, mounting the shoes on the brake plate, holding that in a lathe chuck using a mandrel and carefully skimming the surface of the new brake linings until they just fit into the brake drum. This is no doubt an excellent upgrade but unless you have access to a lathe is impossible to achieve. The main reason for the poor front brake is that for the surface of each brake lining to make contact with the inside of the drum the short brake lever, which operates the cam, is already well out from its 90° starting position where maximum leverage occurs. I have made two little brass plates about 1.2mm thick and mounted each on the end of the brake shoes where the cam makes contact thus having the effect of pushing the shoes outwards towards the inside of the brake drum. I had to reduce the adjuster on the handlebar brake lever to allow for this. I have ridden the bike for about 4 miles whilst continuously using the front brake to help bed the shoes in. The improvement in the front brake is amazing and well worth the effort of making the little brass plates. I held the plates by bending an extra 15mm allowance to the length on each plate onto the same surface where the brake linings are glued, drilling a 2.5mm hole through the plate into the brake shoe (not through the lining) and threading this m3 to take a 3mm set screw. Once the threading is done the hole in the brass place will need to be opened up to 3mm to allow the set screw to pass through it. You will need to measure accurately the size of the surface where the cam contacts the end of each brake shoe - not forgetting to add the extra 15mm to the length to allow for that to be bent onto the surface where the lining is glued. 1.5mm brass plate would probably have worked slightly better but being thicker is obviously harder to bend.

[Pat the Jawa]

Further to my last post - I've been deliberately using the front brake to bed the shoes in and it's got even better! On one occasion I was braking hard and had this squealing noise which puzzled me at first until I realised it was the front tyre squealing on the tarmac. I've started taking my wife pillion at a combined weight of over 30 stone including our gear and have no problem stopping at all

[Blurredman]

Awesome! You've somewhat (somewhat) inspired me to put the drum front back on my ETZ250. I gave up on it and put a disc wheel on and was gradually getting used to it and bedding it in when the brake cable sheath crumpled!!! I do prefer the look of the drum though. It did always interest me that there is enough space in the front hub to make a drum shoe almost twice as wide as it is currently, and that would have been adequate enough to counteract the poor leverage design. But keeping the same size drums front and rear is typically seen as an advantage to the makers of a motorcycle for less hassle and also for the user for interchangeability when necessary. Most manufacturers are guilty of it, and it's perfectly normal practice.

Drum's aren't bad, and people always complain about them for what I perceived as just the usual berating by MZ owners about their front drums, but i've had many bikes with front drums all of them half width like the MZ and they are more than adequate when properly bed in and of a good design. But i've never had a bike where I had to use the rear more than the front in typical daily riding then an MZ 250 drum. They truly are awful.

Just my two pence I'm glad you've got yours working nicely!! I love originality, even more when it works properly.

[DAVID THOMPSON]

your comments bring to mind the drum on the front of my BMW R50s 1963 title
after much looking at how it worked i had a local shop put new fiber on it and made up a stronger cable
with careful adjustment it will stop the bike..ok
but when you stop on a hill while going up
do not release any pressure on the leaver or you will just go backwards and not stop
for some reason it works very poor going backwards when trying to hold it on a hill
normal drill is make sure your in first and hold it with the rear brake
if your in neutral and let off the rear your on your way backwards before getting it in gear
lot of disk brakes installed on /2 BMW's over here. i have seen twin disk setup on an earls fork
dave

[Pat the Jawa]

My thoughts on the MZ front brake were inspired by another bike from the same era which I owned at that time - the Suzuki TS250 trail bike which also had drum brakes all round. Albeit Japanese engineering at the time was probably superior to MZ's but the drum brakes were excellent and very positive. Even though it was a trail bike I regularly had the speedo reading in excess of 90 mph and had no problem stopping. No doubt there was a pretty significant speedo error there but the point being that drum brakes can be very effective. I had considered hunting for a disc front wheel but will be happily sticking with the drum brake now it's working more effectively. Love the look of the front drum brake to

[DAVID THOMPSON]

on a daily driver i prefer a drum its covered and semi waterproof
its a bad day when winter weather freezes your disk to the pads
and you have to haul it home ....been there done that r90s in winter 1976 very wet sloppy snow storm

[breakwellmz]

One of the best brakes i had any bike was a 70s CZ MX front drum brake-powerful and user friendly.I used on my Jawa (350cc twin
h

[Pat the Jawa]

Got a Jawa 350 myself but am spoilt as it had a front disc brake from new - works brilliantly!

[Pat the Jawa]

Further to the original upgrade I removed the front wheel to check on the brake linings. The linings showed even wear over their whole surface which is pretty good so well worth doing. Whilst it was apart I soldered some steel shim to the original brass shim plates to further increase their thickness and hence push the linings even closer to the inside of the brake drum - this has the effect of keeping the angle of the cable in relation to the brake cam lever closer to the ideal 90°. The brake plate mounted shoes only just fitted in the front drum - luckily no brake bind. I have ridden the bike but will have to bed the shoes in again slightly having had it all apart.

[Pat the Jawa]

And yes the front brake is slightly better still - positive with no sponginess and very effective! It's never going to be as good as a disc brake but is very useable and I'm much more confident in my riding now that I know I can stop the bike quickly in an emergency.

[Pat the Jawa]

Thought I'd add that I did the shim upgrade to the brake shoes that came with the bike - the shoe material is a dark pink in colour. Not sure how good quality the shoes are . I bought a pair of EBC brake shoes so sometime I'll add shims to these and install them to see if they're any better!

[Pat the Jawa]

Last post on this subject. Out with the wife today on the MZ so over 30 stone on the bike. Riding along and an elderly female driver looked to be turning right and with no oncoming traffic decided to just stop in the road right in front of me. Jammed the brakes on and stopped with plenty of space to spare. If I had have hit the car it would probably have been deemed my fault but I was more than pleased with the brakes - did swear at the driver somewhat though she couldn't hear.

[tigcraft]

Pat, I'd be interested to see some pictures of the mini mods you've done as Ive just aquired a TS250/1 and will do some mods myself. Ive not taken the wheel hub out as yet to see but I was thinking of making up a twin leading shoe design. I did have a TS a few years ago and always remembered the 'My god I'm going to die' moment which put me off it as a daily rider.

[Pat the Jawa]

I did say last post but have an update to add. Today I fitted the cleaned and polished rebuilt rusty MZ wheel (see rusty MZ post) and whilst doing it changed the original brake shoes for a set of EBC brake shoes. The front brake is quite spongy at the moment as the shoes need to bed in but even with that the brake works loads better. As the shoes bed in I'll post a further update!

[breakwellmz]

DECENT QUALITY CABLES!.......make so much difference.