Trek 800 Sport revamp thread

[DCBassman]

This revamp may take place over quite a long time - you have been warned!
This bike, owned from new, is to be rehashed inot something a little easier for the lumpy bits around here.
It's not light. The standard gearing is too high for me and the hills to cope with. So here's the deal:
I can go two ways with the rear wheel. I can fit an 8-speed freewheel, for example https://www.sjscycles.co.uk/freewheels/sunrace-8-speed-freewheel-1332t/?geoc=US
Or I can go for a new wheel with a freehub. This would enable me to go as far as a 34t low gear, and is my preferred option, if it can be made to work.
Problem I forsee: is the rear OLN spacing capable of taking either the bigger freewheel or the freehub wheel? Much measuring and research needed.
Other than this, I have the E Z Fire combo brake-shifters from the Norco which are compatible all round.
I'll fit a taller, lighter alloy stem. It already has an alloy bar. I have the set of Wellgo LU987U pedals I'd got for the Norco, so that's sorted.
Over time, I will see about changing the chainset from 48-38-28t down to 44-34-24t or maybe lower, to 42-32-22t. @Milkfloat of this parish kindly gave me a Deore LX set, but the chainline didn't match the Norco when I tried it. So I doubt it will fit the Trek either. If not, I will pass it on gratis as did @Milkfloat .

All suggestions, ideas, guffaws and finger-pointing welcome!

 

[Cycleops]

How about fitting a triple if low gearing is your problem?

Sorry didn't read your post properly. That should solve it. Chain line can be solved with a new BB spindle.

 

[DCBassman]

Already a triple. Want an even lower triple!

 

[DCBassman]

With every bike I've had, all triples, the big ring gets little to no use, which was why I was thinking of making a 42 my biggest ring, and going down from there. This would help offset the extra weight of the Trek, about 32lb.

 

[SkipdiverJohn]

I'd be inclined to leave the rear gears alone and just go a bit smaller on the front rings. Most non-race bikes are too highly geared for everyday use, IMHO. It's very rare that you can actually make use of any gear higher than about 90 inches, unless you are on a decent - in which case all you have to do is freewheel. Overly high gearing is totally unusable on a flat-bar bike as you are simply not going to get to 25+ MPH under purely human power without external assistance. Quite a common set-up found on BSO and low-budget suspension MTB's is 42/34/24 combined with a 6-speed 14-28T freewheel. This is noticeably lower than the 48/38/28 normally found on old-school rigids and is no doubt due to the extra effort required to overcome the suspension losses. With 26" wheels that 42/34/24 combination gets you a low gear of 22 inches and a high gear of 78 inches. You might be lucky and be able to pick up a gearing donor cheap, the Apollo CX10 hybrid eBay special I got for a quid.

 

[DCBassman]

@SkipdiverJohn : Depending on which spec sheet you read, it has a 7-speed 13-28 or 13-30. I agree on your choice of chainrings, but want to have that 34t bottom gear. Trust me on this, I need it. If that, combined with the standard 48-38-28 chainrings is enough, job done. If not, I can go further. As is, it, combined with my still slightly excessive weight, goes quite fast enough downhill, the fastest I've ever been on a bike was on this, 38mph coming off the Beacon into Brighton.

 

[dan_bo]

Pics!

 

[DCBassman]

Not got started yet...hang on a mo.

 

[DCBassman]

Trek 800 Sport 1

• DCBassman
• 18 Sep 2017

2002 spec, bought new for £199 in 2001

 

[Ajax Bay]

Best of luck with this project. Hope swimming at Exmouth on Christmas Day won't distract you - trust me, looking down to the beach now it's pouring down and gusting 40+, the mass swim would be a cracking spectator sport today. Even the bonkers kite-surfers have decided discretion is the better part of valour.

I have a few observations. Suspect the 8sp freewheel option to which you link will need a 135mm OLN, which this Trek hasn't got.

want to have that 34t bottom gear. Trust me on this, I need it.

I'd point out that 34t is not a gear it's a sprocket. I'm sure your best option is to go for a triple with smaller rings than currently and a 'normal' freehub/cassette which fits into the dropouts without any cold setting (aka bending and frame stressing) - this one?
https://www.merlincycles.com/shimano-sora-hg50-8-speed-road-cassette-108930.html (13-26)
42-32-22 chainset like this:
https://www.bikester.co.uk/shimano-altus-fc-m311-crank-set-42-32-22-black-404637.html
With 26" wheels 42/13 gives you an 83" gear before 'spinning out' but a 22" one for cranking up to Whitchurch Down.
And the capacity required will be easier for your RD: 33t.
I suspect that a FD designed for a small 'large' chainring will be needed as the cage curvature of a FD designed for a 48t chainring will mean less effective shifting.

 

[DCBassman]

Best of luck with this project. Hope swimming at Exmouth on Christmas Day won't distract you - trust me, looking down to the beach now it's pouring down and gusting 40+, the mass swim would be a cracking spectator sport today. Even the bonkers kite-surfers have decided discretion is the better part of valour.

I have a few observations. Suspect the 8sp freewheel option to which you link will need a 135mm OLN, which this Trek hasn't got.

I'd point out that 34t is not a gear it's a sprocket. I'm sure your best option is to go for a triple with smaller rings than currently and a 'normal' freehub/cassette which fits into the dropouts without any cold setting (aka bending and frame stressing) - this one?
https://www.merlincycles.com/shimano-sora-hg50-8-speed-road-cassette-108930.html (13-26)
42-32-22 chainset like this:
https://www.bikester.co.uk/shimano-altus-fc-m311-crank-set-42-32-22-black-404637.html
With 26" wheels 42/13 gives you an 83" gear before 'spinning out' but a 22" one for cranking up to Whitchurch Down.
And the capacity required will be easier for your RD: 33t.
I suspect that a FD designed for a small 'large' chainring will be needed as the cage curvature of a FD designed for a 48t chainring will mean less effective shifting.

Or this 8-speed freewheel, https://www.sjscycles.co.uk/freewheels/sunrace-8-speed-freewheel-1332t/?geoc=US so it just screws right on in place of the standard 14-30t, along with the chainset you mentioned. Minimum outlay, maximum ease of modification. That widens the gear range a little without overburdening the rd, and if it does, I'll swap the Alivio off the Scott and return that to a proper Sora cassette/rd.

Exmouth nust surely be wild right now...

 

[DCBassman]

Chain line can be solved with a new BB spindle.

In that case, I have the chainset I need. Just need to work out which BB I will need. I'll use a cartridge for ease of install, if I can get one to fit.

Edit: No, I don't think the older Deore LX I have will fit. It's dished right out compared to 'normal'. So the Altus linked by @Ajax Bay will need getting.

 

[Cycleops]

You'll need a UN55:
https://m.bikester.co.uk/shimano-bb-un55-bottom-bracket-square-taper-bsa-68-mm-silver-473987.html
Check the BB width to suit.

 

[Milkfloat]

In that case, I have the chainset I need. Just need to work out which BB I will need. I'll use a cartridge for ease of install, if I can get one to fit.

Edit: No, I don't think the older Deore LX I have will fit. It's dished right out compared to 'normal'. So the Altus linked by @Ajax Bay will need getting.

If it helps - I had a 113mm bottom bracket with the Deore LX on the Trek 970shx it came from.

 

[glasgowcyclist]

My Trek 850 (which I think is essentially the same frame with different components) had a UN73 cartridge for the bottom bracket.
I successfully replaced it with this 113mm UN55 https://www.amazon.co.uk/gp/product/B00653ODZE/ for £11.95.