AHRMA trials

[Ice]

Call CMW.
I believe they carry a rear drum set up that uses changeable sprockets.

 The webstore depicts only a small portion of whats listed in their paper catalog and only a fraction of the warehouse inventory.
 

[darmst6829]

"I believe they carry a rear drum set up that uses changeable sprockets."

Neat. Good to know.

[ace.cafe]

There are also various sizes of crankshaft gears in the primary drive which can be used to alter the gear ratios.

[darmst6829]

Today I took the front wheel apart by unscrewing all the spokes then I disassembled the axle and bearings. A heat gun is your best ally when taking pressed together assemblies apart. I will do the rear wheel and send the hubs off to Matt at Speed and Sport for new Sun rims and spokes. Why not send it straight to Buchanan wheel and spoke? Well Matt does a great job and he will refinish the hubs to my specification. Besides Matt sponsors the AHRMA trials series on the west coast and he is a great guy. 

[ace.cafe]

Pay close attention to the wheel bearings and the spacers. And the bearing in the rear brake drum.
The inner spacers are often not correct length, and often are not cut square on the ends, which leads to the bearings being partly askew when installed.
Also, we have found that the ceramic bearings available at fairly low cost are great in this wheel bearing application. I think they are 6203, if I remember correctly. Reduces rolling resistance tremendously. It has worked out very well for us.

[darmst6829]

I will definitely look the spacers over. The biggest problem for a trials bike is that moisture tends to kill wheel bearings and brake shoes. Generally after a trials it’s a good idea to disassemble the wheels and clean out the hubs of dirt and moisture but that’s not always possible. Do the ceramic bearings come sealed on both sides?

[ace.cafe]

I will definitely look the spacers over. The biggest problem for a trials bike is that moisture tends to kill wheel bearings and brake shoes. Generally after a trials it’s a good idea to disassemble the wheels and clean out the hubs of dirt and moisture but that’s not always possible. Do the ceramic bearings come sealed on both sides?

You can get them sealed or unsealed, or just one side sealed. And the shields/seals are typically rubber, and can be removed or re-fitted at will.
Normally the affordable ceramic bearings just have ceramic balls, and the races are still steel, so the races can still rust. But the balls won't. I guess that's half the battle, anyway.

[barenekd]

Nfield Gear has a brake drum with the fixed sprocket milled off and has a variety of changeable rear sprockets from 38T to 50T. P/N Z91266 and the part name
Bare

[darmst6829]

UPS arrived today with a package from Speed and Sport. It contained a set of weld on foot pegs, new trials bend handlebars and a side stand kit. The side stand is a major pain in the ass and having built one from scratch I know how hard it is to make the thing work correctly and so to me well worth the $130 for the kit. It mounts to the right hand side of the swing arm (or swinging arm) and comes with instructions on how to weld the thing together. The foot pegs look slightly short. I will have to offer them up to the frame and see.

[darmst6829]

Beautifully made English chromed steel control levers, an English built Wassell trials seat and new Enfield front forks from India arrived today. Also I cut out the spokes and disassembled the rear wheel down to the hub. Whoever greased the wheel bearings used enough grease for 10 or 12 sets of wheel bearings and I am not kidding! Both hubs were completely filled with grease. What a mess! The grease had contaminated the rear brake shoes and fortunately I have a new set in the box of stuff I got with the bike. The hubs are going to Speed and Sport hopefully tomorrow.

[Ice]

You can get them sealed or unsealed, or just one side sealed. And the shields/seals are typically rubber, and can be removed or re-fitted at will.
Normally the affordable ceramic bearings just have ceramic balls, and the races are still steel, so the races can still rust. But the balls won't. I guess that's half the battle, anyway.

 This I do with all sealed bearings.
Gently wiggle a tiny flat tool tip in and pop the seals out, flush away the sneeze of shipping grease the factory's are so fond of putting in and re pack the bearing almost completely full with a grease more suited to the environment the bearing will be operating in and then with only thump pressure reinstall the seal.

[darmst6829]

This I do with all sealed bearings.
Gently wiggle a tiny flat tool tip in and pop the seals out, flush away the sneeze of shipping grease the factory's are so fond of putting in and re pack the bearing almost completely full with a grease more suited to the environment the bearing will be operating in and then with only thump pressure reinstall the seal.

Hi Ice,
Are you sure more grease is better? I would be interested to know from an engineering standpoint.
Dave

[darmst6829]

Oh ah before cutting the spokes out and removing wheel bearings spacers etc. measure the offset of the rim.......darn it all the Hell!

[darmst6829]

Well after reinstalling all the spacers and bearings axles etc. back into bare hubs then  installing forks into the lower triple clamp and carefully lining everything up it became readily apparent the offset of the rims is the inner edge of the brake drum for both the front and the rear.  A pain in the ass. The bearings are a bitch. I am sure there is a special tool to reinstall bearings and I don’t have it. After talking with Matt at Speed and Sport I am going to send the swing arm with the hubs as it needs to be modified so the bigger trials tire will fit. This involves cutting out the inside walls of the round swing arm and welding in flat plates creating more room.

[Ice]

Hi Ice,
Are you sure more grease is better? I would be interested to know from an engineering standpoint.
Dave

 Sorry mate, no engineering degree here.  Am I sure more grease is better? for road racing no, for year round riding and jeeping in western WA. and industrial food machinery in sanitizer wash down environments, oh yah    It might be overkill for most folks in America but it sure does rain a lot around Puget Sound.
 I think boaters are in agreement with the principal as they have those nifty spring and plunger loaded axle hub caps on their trailers that keep the bearings full of grease.

 Your forks are bent ? I have a pair of  Yamaha forks and triple clamps that have been modded to fit a Bullet. If you want 'em you can have 'em for the cost of shipping. PM me an e mail address or phone number that I can send pics to so you can take a look before deciding.