Posts Tagged ‘bmx restoration’

haro fusion group 1 si

haro fusion group 1 si

Ever noticed the neighbourhood kid on a BMX who takes all the rough shortcuts while the ‘serious’ cyclists are still pulling on the lycra, clumping around in their cleats and gingerly lifting their high tech wheels over the kerbs before setting off ? Meanwhile, the kid is at the shops already…

Adds a lot to your average cycling times if you consider preparation, doesn’t it ?

Here’s a neat little parallel project then, though it’s not one for me to be riding seriously :

with some rust removed

with some surface rust removed

It would appear that this bike was thrown away due to a non-engaging freewheel after having the top tube multiple-dented, perhaps out of frustration by the (  probably juvenile? ) owner. No structural damage seems to have been done, however.

index marks on dropouts

alignment marks on dropouts

One thing I like about decent BMX brands is the pride of ownership they project into their products, resulting in neat little logos in all sorts of unexpected places.  Also, the weatherproofing of wheel and steering bearings seems better than that of many other bikes, meaning less likelihood of having to find replacements.

BMX bikes are often thrown out much earlier than other bikes, maybe because they are mainly kids bikes and are grown out of more quickly, as well as being less cared for than adult bikes, left outside, crashed, etc.

Though the components are often heavy and oversized they need to be, to cop the treatment dished out by the average young owner !

This frame is Chro-moly 4130 with a chrome finish and a fair amount of cosmetic rust. Only having one rear single-cable Tektro  V-brake means the overhaul should be easier than on my Mongoose Menace with the spinner assembly ( which I haven’t had time to properly finish yet ! )

your typical threadless Aheadset

the threadless Aheadset

The pedals, saddle, tyres, chain, handgrips and brake cable inner and pads need renewing, and these alone can add up the dollars if purchased new. That’s much more than on the rustier Mongoose I salvaged some time back ( unfinished! ), due to this bike being less neglected yet more abused.

The pedal outer bearing races are dry and ruined, and so far the rear wheel needs a cone and bearings renewed but the rest is OK.

Once again, I’m not concerned about the finish being immaculate and I’m not willing to source shiny NOS components as some perfectionist restorers do. However, it’s important that everything works smoothly and safely and the best way of achieving this is via a complete strip-down.

large cups - typical one piece crank set-up

large cups – typical one piece crank set-up

Except for the steering cups and lower fixed cone, and the large bottom bracket cups for the one-piece crank that is …

I believe that if they aren’t worn, then leaving them as fitted in the factory will keep them running truer than removing and refitting them and they can be cleaned quite well in situ.

There was a lot of rusty crud in the bottom bracket shell and steering head tube that needed clearing out, but the bearings are OK – I wouldn’t have left it any longer though …

like the rising sun

like the rising sun

The one-piece crank is heavy steel, but with a nice looking ‘old school’ 44T alloy chain wheel attached. And here’s what your typical BMX steering system looks like, in pieces :

steering bits

the steering bits

Not sure if the brand is “Fusion” or “Haro” as a number of the parts are stamped “Fusion”.

The age ?  Well, the levers are stamped ’97, in which case it’s older than I’d guessed.

To be continued …


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so much rust …

Well, it’s been some time since I’ve looked at this baby – nicknamed “Dennis the Menace” –  it’s a 2004 “30 Year Anniversary” Mongoose Menace Pro, found last year as hard rubbish in a sad and rusty state.

the colours of rust – yet so much promise

And yet it was complete, with good tyres and saddle, the only thing noticeably broken was the flimsy plastic chain guard.

it’s time to dust off the cobwebs

With this kind of rebuild you may need very little money but also a lot of time to work on the rust and make good cosmetically  ( if you are concerned about cosmetics of course ).  Even if not, the bearings all need cleaning, re-greasing and adjusting.

the rear wheel – as found

If you don’t enjoy this kind of work then buy yourself a new bike and enjoy riding that, the same applies if you are the sort of person that frets about hourly rates and such, as you could probably buy two new bikes for the hours a bike shop would charge to do this super-fiddly job !

rear brake

But if you like tinkering occasionally, are not in a hurry, and find this work relaxing, the cost is little if you have a few bike tools already. For this bike I needed to buy a 17mm cone spanner for the heavy duty wheel axles, that’s all.

fork refitted

Anyway, re-assembling the steering head is just the reverse of Part 2 – except that the holey top nut is tightened down finally to take up any side play before the bar stem is tightened onto the threadless steerer to hold the adjustment. The fork was de-rusted and repainted gloss black, avoiding the decals. The “cane creek” steering bearing seals seem very water and grit entry resistant on this bike, having quite fine gaps.

the bb, with cranks off

and here are all the bits…

The Mongoose bottom bracket is very similar to a one piece crank in that it has large diameter pressed in races with left hand threaded adjusting and lock nuts on the non drive axle side. The difference is that the cranks are on either a splined or hex axle with ends that have retaining screws and the cranks themselves clamp onto the axle with their own bolts.

the re-assembled bottom bracket

The BB can thus be assembled without needing to risk damaging the chain wheel while rebuilding. Cheapo BMXs have one piece ( a.k.a. Ashtabula ) combined crank/axle. The steel cranks on this bike weigh a ton – and I can’t believe how heavy a 20″ bike with alloy wheels can be !

Some time ago, I overhauled the wheel bearings cleaned and tidied up the wheels, de-rusted and painted the spokes and blacked the tyres so they looked new ( Mr Keen ! ). I now only had to adjust the cones and fit them to the bike frame.

a big improvement – but is it right way around ?

The handlebars were a fantastic green/orange/grey colour because of corrosion, and I sometimes wish I had maybe just clear coated as they were, because the efficient rust converter stole this colour and forced me to repaint them – sometimes rust is beautiful…( can’t believe I just wrote that ) ! Then again, it was lumpy and rough, and might not have lasted.

full a-head …

I have left the brakes and cables for later, as these are somewhat complicated compared with a normal bike. Suffice to say that the fancy silvery braiding inside the cables is very prone to rusting and the plastic outers offer very little protection to it from the sun and rain. Can they be re-used ? We shall see.

some more progress

This isn’t a journey back to childhood, as you may be thinking – There were no BMX bikes around when I was a teenager, it was Dragsters and such back then – those used to lift the front wheel dangerously when you pedalled at all hard. I still think they are dicey now, and they definitely were then !

However, it should be fun messing around on an old-school BMX for a while …

P.S. You can tell this is old-school because the rear cog has more than 9 teeth, the front more than 20, and the seat doesn’t point up straight off the seat tube at some lewd and silly angle toward my designer undies – and that’s the way I like it thanks !

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The Mongoose Menace is a sturdy little entry level BMX. Unlike some cheapie BMXs it has closely spoked wheels with heavy duty oversized axles and a decent – if weighty – component quality. The steering head is an Aheadset type where the stem clamps on to the fork tube “steerer” There is a threaded top cap with a hole in the centre to allow the front brake cable to run through the centre of the fork steerer. The elaborate rear brake arrangement uses split balanced cables and a rotating cable joiner/bearing assembly that allows the bars to be spun round and round without snagging the cables on the steering head. It’s made this way to allow for stunts when riding. Although the rotating brake arrangement isn’t relevant to non-BMX bikes the typical so-called “threadless” headstem is in principle similar to those used on most modern bikes.

dennis the menace

Here are some more views of this sad case of a bike as it was, to show the assembled steering head and brake arrangement :

brake cable layout

front view of bar clamp

Once the brake components, bar stem and bars are removed the steerer needed a good whack directly on the top with the hammer shown, with a rubber protector fitted. I also left the steerer cap on to avoid thread damage to the steerer while hitting it .

tools of trade & steerer released

the bits 'n' pieces

Now dismantled, top row L —> R are brake spinner bearing & spacer, bracket for split cable, spacer, bar stem, spring washer and top cap with hole for front cable

Bottom row L —-> R lower bearing race cover/seal, 2 caged bearings, head race, top race cover/seal and a plastic sealing wedge.

The lower fork crown race will be cleaned and left on the fork for reassembly and the bearing cups left in the frame and cleaned.

I’ve left out the cables to avoid confusion.

Started to de-grease the bearings with kerosene and de-rust the other parts with rust converter — The latter is a magic liquid based on Phosphoric Acid that converts red iron oxide rust to a stable black iron phosphate. There are many different brands of this available from hardware and auto stores.  It’s a must have …..

it's magic ! rustbuster & kero ...

This last component is the bearing for the rear brake cable transfer – it contains many small ball bearings and doesn’t appear to easily dismantle. I’ll flush it as best I can with kero and re-oil it . It’s not a highly stressed bearing, it just has to run freely, so that should be OK.

ball bearing race for rear cable "spinner"

I hope this isn’t too boring for non-mechanically inclined cyclists, I will try to split these posts up a bit …

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Complete, but pretty sad ...

My latest find is this 2004 Mongoose Menace Pro 30 year anniversary BMX bike. It has been badly neglected, being left out in the weather before being dumped for pick-up waste with some other bikes, where I happened across it by accident. While BMX is not my scene, I think it’s an interesting little bike, it’s made in Taiwan, with a cro-moly and hi-ten steel frame painted in a sort of battleship grey with some gloss black and has lots of Mongoose logos on it.

... and left in the weather

I haven’t had a chance to closely look at it for faults, but it looks complete and is in reasonably good nick mechanically, but very sad cosmetically.  This will be an occasional project for when I have bits of spare time in between other things, as it’s not something I can really use seriously. I also think it should be kept as original as possible because of the appeal of an “Anniversary” model.  I can see why it was dumped, but surely it’s too good for scrap ?

handlebar sticker

head details

I would think that it may be collectable at some point in time, if it is not already so, which is why I need to give some thought as to the best way to overhaul and partially restore it, keeping some patina and the logos if possible, while preventing further rust and decay. BMX bikes have a somewhat different steering head and brake cable set-up to other bikes, as well as heavy duty axles and lots of spokes to allow for stresses, and it will be useful for me to see how it is put together.

and plenty of rusty spokes

from above - seat is OK

This bike recalls to mind the words of Steven Lindblom  “substitute your own labour for money, and don’t spend a cent more than you have to” when discussing reconditioning bikes with a vague idea to sell them. I see this as an example of the law of diminishing returns where all the individual new bits can often add up to an expensive rebuild when compared with someone buying new…

and more surface rust...

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