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Peter_B

Anybody know anything about mountain bikes?

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During my recent lockdown clear out I "excavated" my old bike from the junk in the garage.

The bike is a GT Aggressor 2006 model. Nothing flash, was cheap at the time.

I used it a few times shortly after I got it (in 2007). Since then it's been stored either in my parents garage or my garage.

It's in quite decent condition considering it has been neglected. It needs a clean and some oil etc. The tyres are probably shot so I've got some new ones on order.

But that's as far as my bike expertise goes.

The gears seem to need adjusting, as do the brakes, but I haven't a clue where to start.

Also one of the rubber caps/covers on the front suspension fork has perished and I don't know whether that is something crucial.

I'm just thinking of getting it usable again so I can use it for a bit of exercise.

So, anybody who knows about these things, have you got any advice or guidance for me?

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We had a whole thread on bicycles somewhere deep in this sub-forum, with plenty of mountain bikers and a few mechanics active on there. I am sure from there, someone knows a thing or two about bikes.

From what I can gather, though, the bike could use some new cables and housings to start. As below, the cable is the metal wire with the short cylinder on the end, and the housing is the sheath:

35750.jpg

A bike that has been sitting that long will likely need new cables and housings for both the brakes and the gears. Brake cables are thicker than gear cables. The housings are different for each: gear housings are made up of axial strands of wire, as in the above picture, since the housing is not supposed to compress. Brake housings consist of metal coils, being able to compress:

311-154_MD.jpg

In a pinch, you can use gear housing for both brakes and gears (provided the housing can accommodate the brake cable), but shifting performance will usually suffer if brake housing is used for both.

If you see "Universal" housing, it is made of braided wire and is thus suitable for both uses.

I would think that full replacement of the cables and housings would be a good place to start, since having these new facilitates adjustments on brakes and gears. Sometimes, braking and shifting problems are even caused by dirty cables and/or housings.

From there, adjusting the brakes is usually a matter of getting the cable tension and pads set right (there should be a screw on each brake arm that helps with spring tension - they can be used to adjust the pad's distance to the rim, as I see the 2006 GT Aggressor had V-brakes), and adjusting the gears is about getting the cable tension and the end points set right (there should be two screws on each derailleur - each one determines how far the derailleur will go in one direction).

Be sure to lubricate the pivot points on your derailleurs and brakes - I like Tri-Flow PTFE lubricant for this, but in a pinch chain lubricant can get things moving again. WD-40 is really only suited for freeing seized parts; it evaporates quickly after that, leaving not a whole lot of anything to lubricate the part afterwards.

Bad shifting after new cables and free-moving parts can sometimes be due to a worn or rusted chain. As it had only been used a few times, the chain is probably not worn, but it could be corroded. Stiff links from said corrosion can inhibit shifting, and a badly-rusted chain is very difficult to restore. If the bike has only been used a few times and the chain is corroded (either stiff, squeaky, or both), a new chain will help.

As for the rubber cap on the suspension fork: the caps are usually seals for the suspension system, but are more important for air- or oil-filled suspension forks. It looks like the GT Aggressor had a simple friction coil-spring fork, so the seal may not be a problem except for aesthetics. I remember seeing plenty of friction-damped suspension forks without rubber caps that operated normally.

Best of luck! I hope you can get your bike up and running again :)

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@Grastens thanks for the info.

I hadn't thought about new cables. I kind of thought that as they hadn't had much actual use they'd be ok.

Probably does make sense to replace them though.

Do you know if these will do the job?

Brakes - https://www.wiggle.co.uk/shimano-road-and-mtb-brake-cable-set/

Gears - https://www.wiggle.co.uk/shimano-mtb-gear-cable-set-with-stainless-steel-wire/

 

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Indeed they will!

The deal with replacing cables is that as they are under constant tension, they do stretch and go out of adjustment with time. I find that a good number of them also corrode over extended storage, though less so when stored indoors.

A dedicated bike cable cutter will go a long way for ensuring clean housing and cable cuts. Otherwise, make sure your side cutters are nice and sharp, and if your cutters mash the housings shut, you can open up the ends with a pick or awl.

Best of luck!

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Your local reputable bike shop will get it up and running safely for £100 or so including new cables and outers if they need doing. If you can stomach that, my advice would be to get it looked over by the professionals. 

If you want to fettle yourself, brakes and gears have adjustment dials that counter the small amount of cable stretch you get. Dialling them out gives you more tension, dialling them in, less. If you can figure out what you need to do it's reasonably simple - plenty of instructionals on youtube. 

You might be able to save the existing cables by re-lubricating them - a drop of chain oil on the inner cable as it exits the outer will then run down in to the outer with a bit of persuasion. 

The suspension fork...eh it will be fine. Those cheapy forks don't do squat anyway ;)

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Howards is right about lubricating the cables - I guess my first instinct as a former shop mechanic was to toss them :P So long as they are not frayed, kinked, or corroded, perhaps all they need is some adjustment.

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16 minutes ago, Howards said:

Your local reputable bike shop will get it up and running safely for £100 or so including new cables and outers if they need doing. If you can stomach that, my advice would be to get it looked over by the professionals. 

If you want to fettle yourself, brakes and gears have adjustment dials that counter the small amount of cable stretch you get. Dialling them out gives you more tension, dialling them in, less. If you can figure out what you need to do it's reasonably simple - plenty of instructionals on youtube. 

You might be able to save the existing cables by re-lubricating them - a drop of chain oil on the inner cable as it exits the outer will then run down in to the outer with a bit of persuasion. 

The suspension fork...eh it will be fine. Those cheapy forks don't do squat anyway ;)

Thanks. Unfortunately I don't know of a good bike shop near me. The ones there were closed a few years ago. Just Halfords left as far as I'm aware.

Certainly on the brakes, the adjusters at the lever end are fully wound in. The front cable needs loosening as those brakes are binding.

Rear brakes seem ok but perhaps should be loosened at the brake end so I can have some adjustment at the lever.

Part of me wishes I could find a modern equivalent of the Raleigh Montage I had as a kid :D

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I've found a cycle shop that is only about 10 miles away. Didn't know it existed before now.

Their full service price is bang in the range @Howards suggested at £110. I sent a message through their website and the chap responded already and reckons it might be able to be sorted on one of their lower priced service packages.

So I might well get them to look at it. By the time I've messed about getting parts etc it probably wouldn't be far off their price. Plus they know what they're doing! :P

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@Peter_B The gears will be indexed. When a cable stretches, you can use the barrel adjusters on the ends of the cables to line the rear mech up with the correct line on the sprocket.

Your 1st point is to set the end limit adjusters (2 screws on the rear mech). These stop you sending the mech past the end of the required run.

Drop the mech into the lowest (smallest) gear, and make sure that the jockey wheels on the mech line up the with corresponding freewheel sprocket. If they don't, adjust the H screw until they do. If the screw isn't labelled, and you don't see it move, set the screw back to where it was and turn the other screw.

Then, with the back wheel off the ground, use the gear lever to go through the gears one at a time. The jockey wheels should stay in line with each ring on the freewheel. If they don't, then you need to adjust the barrel adjuster on the mech. This is the little furled nut between the end of the cable and the rear mech. Turning this changes effectively the length of the inner cable. Once the jockey wheels and freewheel line up, the gears will stay like that. 

 

When i fit a new cable, or build a bike, i set the end limits of the rear mech without the chain on first. You don't want the mech to travel too far inwards and meet the spokes. That's not good......

 

Follow this simple guide if what I have said doesn't make sense:  https://www.cyclist.co.uk/tutorials/74/how-to-adjust-a-rear-derailleur

 

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@FoxShot thanks for that. 

The bike is actually with the local bike shop now, they've had it for a few days so I'm hoping it will only be another day or so before it is done.

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Yeah, i saw that. It was more aimed at helping you to keep it running. Gears look complicated, but are mad simple when you know how they work, and how to keep them working. I have been riding for WAAAAAY to long. Used to be a roadie, now, Mountain bikes. :)

 

 

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