4 Aug 2014

4th August 2014

Monday 4th 62-75F, 17-24C, heavy overcast, quite still. A damp start is forecast with warm sunshine later.

Statistics suggest the use of headphones while cycling increases the risk of having an accident by 30%. While 10% of those injured on their bikes admitted to having used a mobile phone or had listened to music immediately before their accident. Now the professional liars politic-ooze are considering how to reduce the problem.

I can never understand anybody listening to music while jogging or riding in the countryside. They miss the connection with nature, the birdsong and so many natural sounds. They also completely miss the sound of fast approaching vehicles! Never mind a cyclist struggling to pass you as you meander along in the middle of the cycle path in your own little, fantasy world. If you miss a beat to jog or cycle to then perhaps you should try listening to your own panting breath or heartbeat? Become more self-aware? Suit yourselves. You will anyway.

It was warm and bright for my walk around the bare fields and shady woods. Since I have started wearing shorts for my morning perambulations I have struggled with grass seeds and burrs stuck to my socks. I am not aware of them at the time but my socks are often covered in debris when I take off my boots. My legs are now so brown that my bare feet look like I have been standing in a bowl of whitewash. No sign of rain yet. Still lots of fields left to harvest. Large flocks of Sparrows everywhere.

After a struggle my wife finally managed a sharp image of a Brimstone butterfly. The Canon Ixus 117 camera has a mind of its own on auto! Without having the zoom range for decent image scale. Cropped from the original. Fame at last! 

Rode to Assens to shop. Breezy but mostly crosswind. Not quite as warm as last week. Which is a great improvement! Going well. 21 miles.

I have spotted the rear gear cable is fraying at the ShiftMate. It has also frayed at the changer clamping screw. IT may be a poor quality cable. I have no idea as to its exact origin. It having been selected from my poly bag stock of unused cables. I may discard the ShiftMate when I change the cable. It does not provide the flawless index changes I'd hoped for.

While I had the trike up on the stand for examination I finally decided to have a proper look at axle friction. It has been bugging me for ages that the Trykit wheels stop very quickly when given a spin. Unlike the Higgins which also has has the Trykit 2WD system fitted. The Higgins wheels go on spinning for minutes. The main difference between the two trikes is in the size of the journal axle bearings. The Higgins being limited in bearing size by the need for them to fit the adjustable [bottom bracket] cups. Still, the difference in bearing size should not have that much effect on axle drag.

I have frequently been dropped on descents while pedalling flat out as an ordinary cyclist simply free-wheels effortlessly away from me on a sit-up-and-beg roadster with fat tyres. It goes without saying that drag on descents is matched by drag on climbs and on the flat. I obviously have to work that much harder to overcome the extra drag. Though speeds are likely to be higher on descents than elsewhere the difference is probably not that great in practice.

First I removed the wheels, outer bearing circlips and then withdrew the axles. Allowing the cassette to drop out into a rag on its 2WD double free-hub. I then reinserted the axles and refitted the outer bearings and their retention circlips.

There really was am awful lot of drag when trying to turn the bare axles by finger pressure alone! So I removed the circlips and bearings again. Each bearing had roughly the same amount of drag when a finger was inserted into the bore and the rim pushed around.

It had already occurred to me that only one side of each bearing is exposed to dirt and the weather. The inner seal is thus extra baggage. I could reduce seal drag by half simply by removing the four inward facing seals. The axle housings offer perfect protection for the bearings. So there was no need to worry about contamination. Any dirt would have to get past the outer bearings with their intact outer seals. A very unlikely occurrence.

I examined each bearing carefully and removed the worst seal from one side only with a small, sharp screwdriver. The original packing grease was still adequate but I added a good dollop of new grease anyway. I always smear the entire axles and bearings with grease to stop potential rusting between maintenance sessions.

After re-assembly the axles seemed to turn slightly more freely. With the wheels in place they spun for far longer than before. It should be remembered that the 2WD pawls and support bearings in the special free-hub also add to friction when freewheeling. Not that I do much of that even on descents. So the 2WD free-hub can probably be ignored provided I  keep pedalling hard. 

I still have some worries about my Trykit's excessive axle friction. My Higgins needed a 4mm gap between the stub axles. The Trykit has only 1.5mm clearance between the inner axle stubs but still has a 4mm central spacer in the 2WD free-hub. I'm wondering if this increases end loading on the axle bearings. And, more importantly, whether it really matters.

One way to change the end loading would be to turn a millimetre from each inner bearing, axle shoulder. While I do have ceramic tools for my lathe and the skill to do it it would be rather a drastic move. I would have to discuss the possible consequences with Geoff Booker of Trykit first.

The other, far simpler alternative would be to make or use a thinner central spacer. The great width of the free-hub ratchet teeth should easily cope with any minor, longitudinal repositioning.

I am still unsure whether the bearing retention circlips need to be preloaded for safety. The circlips are the only thing which stops the axles from sliding out on the corners. A well proven design, long used by George Longstaff, I believe, before Trykit adopted the same arrangement. The circlips expand into a groove cut into the inner circumference of the bearing housings.

The circlips themselves seem to be stamped from sheet material. Producing a handed appearance. With more rounded edges on one side and sharper on the other. I always place the shaper edges outwards to ensure the best possible location in the concentric, bearing housing grooves. I then use the slide hammer weight, provided by Trykit, to ensure the circlips are properly seated.

Click on any image for an enlargement.

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