Retro bike fan

So, i recently bought a coaster brake hub and i have laced a 700c rim for this hub. i needed this wheel for my 1988 Carrera Alpina road bike. My problem is that when i coast and i just hit a little bump a rattling / clunking sound appears, but when i slightly engage the brakes and hit those bumps again the sound disappear. i already have checked the chain tension and that everything is thight. i think that something with the internals is going wrong. What is your opinion?? do you have any solution for my problem? Thanks.

dedhed

First tell people what brand/model hub it is.

Iride01 

So when you converted from a multi-speed rear to a single speed rear with coaster brake, did you check whether the new hub was putting your chain line in the proper place relative to the front chainwheel or chainwheels?

I am partly imagining that your chain-line is off so much that your chain is wanting to "shift". However if you have it so tight that it can't do that, then it might make all sorts of noises at various times.

Andrew R Stewart 

The internals of most modern coaster brakes are fairly simple. The factory lube will in time get washed out from rain, degrade from time alone and get all gritty with use anyway. I suggest taking it apart, cleaning and looking at the parts for damage/wear and reassembling is all looks good. A dry bearing and or coaster brake shoes/pads can cause noises with no other damage. Andy

Retro bike fan

Well, my coaster brake is a cheap ventura hub. The chain line seems pretty straight but the chain is tight and i dont think that the chain hits the frame. Maybe is something with the internals. The noise is happening only when i am coasting or when i pedal and i hit even the smallest bump. When i backpedal to brake there is no noise whem i hit a bump. Maybe thus can help you understand better my problem. Also i bought the hub new and the the grease should be checked from the manufacturer. Any other suggestions?

Geepig

Well, there is no guarantee that because a hub is new to you it does not mean it has not been sitting around for a long time, so the greasing question is still valid.

How tight is tight? Like a bow string or with about half an inch / 10 mm play up and down? When you reverse pedal, does it take about a quarter of a turn at the pedals to engage the brake? More? Less?

Are you 100% sure that the brake arm is strapped securely to the frame?

When you installed the wheel in the frame, did the hub fit snugly between the dropouts, did you have to bend the chain and seat stays inwards first, did you have to use spacers, or did you just wind the wheelnuts in until the frame gripped the hub?

Is your chain / chainwheel / sprocket all of a similar type and new/old?

Are your cranks fully secured? Is the BB good?

Is the rear sprocket installed snugly?

The reason that I ask is that when you brake all the chainline components are stationary and under load, while when pedalling the chain tension is different and while coasting their should be little tension anywhere - and nothing is stationary.

Retro bike fan

There is 5 mm play up and down in the chain. Also, i need to backpedal almost 1 quarter to break enough so i can decelerate. Unfortunately the hub did not fit the chainstays pretty well and i had to snug the nuts so it can be securely tightened. The coaster brake cog is fiemly attached to the wheel. But the front chainring is old and the back is newer but both seems to be in perfect condition. To sum up, everything seems perfect to my eye and experience, except the noise that makes when hitting bumps.

Andrew R Stewart 

I will suggest all is not perfect if you had to close up the frame's rear width to get the coaster hub to secure in the drop out slots, to start with. Then there's the unknown unknowns We've been trying to explain some to you. When you can't see or understand what's behind the curtain it's time to pull the curtain back and see more. Andy