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