Amp Research B4 1997 - updated on progress 1.6.10

After several long, wet and dirty rides over a variety of surfaces and terrains, I have decided that the rear brake is just not good enough, and rather than simply change the pads to Green all weather ones, I'd rather fancy a challenge.

My aim is to run Hope discs front and rear. After some responses from other forum users with detailed pictures of the Hope kit of the same era, I decided that I was quite disappointed with Hope's efforts and I could do better. It's the whole arrangement of the funny long bolt on skewer and short axles that I found weren't required.

My thoughts are to use a Silver Hope rear hub with 32 holes and the matching 5 bolt spider. This should be the standard axle version that appeared slightly later than the Ti Glide. I managed to find one of these on ebay for under £23. Bargain!

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It's worth pointing out that I won't be using the near mint Mavic 217 ceramic rims either. A good friend has agreed to take them and replace them with a decent disc rim of my choice. It will probably be Mavic 317's, and he'll take the White Industries hub to match up to his pace RC50 front hub on another Amp B4.

Next, I will need a matching lever for the left hand side (still looking), and some braided hose (because it's prettier and will match the front). I will be able to route the cable along the downtube out of the way, which is far better as well. I hated the zip ties on the top tube!

I am unsure of the caliper to use, and will try several Hope C2 options as some seem better suited than others, due to their mounting design.

I have pre-tested one of these hubs and discs in the Amp rear end and the disc spider catches the horst link bolts by about 2.5mm. For this I will need to fabricate some recessed horst link bush and bolt kits. I have the exact set up in mind, and it's much better looking too.

As I'm restricted to 155mm disc at the front, then I shall run the same size on the rear. I already ordered this direct from Hope with the chamfered bolts and holes.

Finally, i will make an aluminium adapter to fit the Amp disc mounts, and use some Ti bolts to hold it together.

I'll welcome feedback on my ideas and any help with parts would be appreciated. A suitable caliper and lever is next priority.

Also, Onza headset will change soon. They are just awful. Bring on the King!
 
Managed to find a Hope No. 3 caliper for £20. A bit dearer than what I wanted, but the mounts and hose points seemed closest to what I was looking for, so worth extra pennies. I'm trying to make it as close to the seat stays as possible, for a cleaner look, and also a smoother line for the hose to follow.

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After sourcing some more bits and pieces required, I made a mock up of what I'll use as a rear brake.

After a search in my uncle's shed one night, I came across a spare Amp rear end from a B3. What was most interesting were the horst links, as they were recessed.

I borrowed the B3 rear end to use as a work bench.

I made a very rough cardboard template for the disc mount, and used some spare bolts of almost appropriate length to hold it all in place. Some trimming is still required to get it a bit prettier (and lighter) when it's made in Aluminium. I will use the straight edge of the Amp dropout to my advantage by dovetailing the disc mount to it, so braking stress is fairly distributed.

The tolerances between disc and horst link are very close, but adequate.

Next up is to perfect the cardboard template and then measure the different wall thickness required throughout the disc mount.
I could make the mount in the shape of the template in plate stainless steel. It would just need threads welding to the back of the plate for the dropout bolts to attach. This method wouldn't make use of the dropouts flat edge to support the braking forces, but would probably look neater, and be much cheaper to produce, and reproduce!

The plan is to use a right angled hose, which will curve down beautifully to the chainstay where a little Amp Research (currently redundant) cable guide awaits it.

The usual camera is on charge, so pictures are a bit poor, but I'll get some better ones soon.

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your disc tab adapter

Before you go any further with this project!

I have just designed and manufactured a nice aluminium disc adapter to run an IS standard disc brake on my AMP F3 XC fork.

I have in my posession a technical drawing for this, but more importantly for your project, I have all the technical drawings for the AMP rear end, which were kindly given to me by AMP. This will help you create the correct hole pattern for your adapter, then, just find a helpful local machine shop who will CNC you one up. Don't forget, you need to get the offset right aswell so the disc lines up nicely with your caliper.

Send me a message if you need the drawings.
 
Here is the latest update for anyone interested.

I have had a busy few months moving house and all things bikes have been put aside slightly. Well, I'm back on it now, and with full force too.

I managed to get some Grey 317 disc rims and swap them into my wheels, but with the addition of a new rear hub mentioned earlier. The old White Industries rear hub and Ceramic 217's have gone over to HarryCrumb in a deal.

I built the wheels with alloy nipples to lose some weight. I then aquired another 5 bolt 155mm rotor to match the front. This had to use chamfered bolts to clear the horst link. I made sure I used threadlock on them, as I have had discs come off on rides when it's not used!! I kid you not.

After an hour fishing around the workshop of Leisure Lakes bikes, we found all the necessary bits for the job, including braided hose, bleed nipples, hose attachments, sintered pads and a brand new pro lever. I should mention that I actually sold the mini caliper from earlier pictures as I didn't realise I already had a C2 one sat in a box in my shed! Embarrasing what I forgot I owned.

My cardboard homemade disc adapter was sent off to a guy in Nelson, who was confident that he could copy my template and drawings for about £15 posted. This would be in 2mm stainless, and to be honest weight is not an issue. You can hardly tell it's in your hand. Some people felt that the 2mm steel would not be strong enough, but my theory was simple. If the disc is 2mm and the caliper is practically held in place by the caliper when the brakes are applied, then why would the adapter need to any stronger than the disc?

Anyway, the pictures speak for themselves really. I'm quite proud, as the disc is exactly in the middle of the caliper without any work required to my original template, and no spacer washers were needed. Luck or planning? who knows! For anybody wishing to do the same, the templates are available from this guy... http://www.cylex-uk.co.uk/company/j-ros ... 28877.html ...and probably for about £10 posted.

Also, after a big Lakes ride, the frames main pivot was practically hanging off, so I took the liberty (read essential work required) of ordering some new horst links and a main pivot from Brion at Amp Research.
Some of you may notice that the horst links are different from those usually found on Amps. These are the early type, which clear the disc. They can be made by threading the steel washer with an M6 thread, and then using a button head M6 bolt inside of the M5 nut and bolt arrangement. Brion said that you could turn the link around the other way, but this looks neater.

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During the weekend in the Lakes, it was clear that the Gore cables were quite useless, and were working on some kind of delayed ESP shifting, so I replaced them at the roadside from a LBS. When I got home, I ordered some braided outers to match the brake cables.

Oh yeah, the Amp was fantastic on the trails. I absolutely loved every minute of it. It really can handle quite a lot. It's probably best on the flowing singletrack through the woods. I couldn't believe how fast it was but still fully controlled.

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