Bicycle Mechanics - Upgrade drivetrain on MB
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12-18-01, 07:33 AM
I have a Diamondback Sorrento as a commuter. A $199 bike in near perfect condition with an Acera X drivetrain and a solid chromo steel frame and city slicker tires. Good is good, but better is better, and perfect is what I strive for. I would like to go to a Deore LX or XT drivetrain one piece at a time starting with the rear derailler. Is it going to be any smoother\better. Could I upgrade it enough for under $150 to make a noticeable difference. Or should I save up for a new bike already equipped. I'm thinking of new pedals too, I heard some creaking under extreme power up a hill yesterday.
12-18-01, 07:55 AM
If you like the frame, I'd have thought it was worth upgrading the rest unless the cost of the individual bits of the chainset start coming very close to a new bike, with a similar chainset fitted.
I toyed with the idea of upgrading bits of mine as and when I have a bit of spare cash, some bit's seem very cheap (like front mech's) other's like the rear a lot dearer.. of course you use the rear a lot more. I'd be interested to know what upgrades give the biggest improvement for your money.
If you don't mind friction-mode shifting (which is all I ever use), you have lots of mix-and-match options and can easily perform piecemeal upgrades. Watch for clearance sales and eBay deals on components, do your own work, and upgrade opportunistically. Otherwise, you will find it more cost-effective to accumulate your lunch money towards a complete new machine.
Last year, I bought an aluminum-framed Ross mountain bike at a yard sale for $20. The hubs, pedals, and cranks were cr@p, but the frame was suprisingly decent. I bought several new components for it: Shimano/DT/Mavic wheelset ($85, Supergo.com), White/Sugino crankset ($50, sheldonbrown.com), Wellgo pedals w/ clips and staps ($30 at my LBS), SRAM PC-58 chain ($20, LBS), anatomic GT saddle ($16, eBay), and KoolStop brake pads ($16, LBS). I would put the final result up against any new bike in the same low-200s price class. (If I had patiently waited for the right deals on used equipment, I could have done the project for about $150.)
12-18-01, 09:09 AM
Since you're starting with a $199 bike, it seems kinda crazy to spend another $150 in parts right off to make it run smoother. I would "try" and be patient and wait till the parts wear out and then upgrade.
IMHO if you want your drivetrain to shift smoother and you brakes to respond well, invest in some good cables and housings. A full XTR groupo will work like SHE-AT if the cables are crudded up and rusty! A teflon coated cable or a lined cable housing makes a "HUGE" difference! If you don't want to do this, make sure your cables are kept clean and put some lube into the housings on a regular basis. I personally will drip some Tri-Flow into the housing ends at least once a month. You can do this without disconnecting them from your bike.
Let me try to explain. Shift your front derailleur (left shifter) into the big chainring and then w/o moving the cranks click the shifter or rotate the Gripshift into the small gear. This provides slack in the cable and will allow you to pull the housing away from the frame stops. Move the housing back and forth along the cable while dripping lube into one end. Put the housings back on and pedal the bike. Now do the same thing with the rear derailleur and the brakes!
Once the drivetrain wears out, I'd replace parts in this order:
1)chain-your chain will wear out first and is the cheapest to replace
2)cassette-your cassette usually wears out with your chain, but if you replace your chain regularly, you can usually get 2-3 chains per cassette
3)shifters-good shifters will "feel" crisper and make a more significant difference in shifting (IMO) if the derailleurs are adjusted properly. Front shifters are the most noticable between a low-end and a high-end shifter.
4)cranks & bottom bracket-Stiffer cranks will make a noticable difference and better cranks usually come with aluminum chainrings (lighter weight) and usually have "ramps and pins" that help shifting. Replace the bb at the same time for compatability reasons and stock bb's are usually VERY CHEAP and VERY HEAVY!
5)rear derailleur-You would have to change this sooner if you are upgrading from 7 to 8 or 9 speed! I would wait on the derailleur, only because they cost a lot and the differences aren't THAT significant!
6)front derailleur - same as rear!
I'll probably get a lot of dissagreement on this, but that's what I think! I've changed my LX shifters to XT shifters and it make a BIG difference. I've changed my alivio rear derailleur to an XT and it made a difference, but not so much. I did the same thing to my wife's bike b/c she had problems (not enough strength) shifting the front derailleur. After I swapped the shifters, she didn't have any problems.
This is just my opinion. I think too many people put too much emphasis on the derailleurs and not the shifters!
12-18-01, 12:26 PM
Here are some good prices on some of the stuff you need to go to a 9-speed Deore XT system:
Deore XT Rear Derailleur - $39.95 at nashbar.com
XTR Front Der - $29.95 at nashbar.com
Deore XT Rapid Fire Shifter/Brake Levers - $69.95 at nashbar.com
One of the following depending on your current system as discussed below:
Shimano HG-70 9-speed cassette 11-32 - $32.95 at nashbar.com
Zak19/Alvio 8-speed hub rear wheel - $46.95 at nashbar.com
(I am not necessarily recommending this wheel, it is just an inexpensive option)
HOWEVER - Is your Alivio 7 or 8-speed? Is the rear hub a freewheel or freehub? If it is 7-speed it may be a freewheel, and you will have to get a new wheel. If it is an 8-speed, it is probably a freehub and all you have to add is a 9-speed cassette.
How do you tell the difference between a freewheel and a freehub? Here's how I tell. Remove the wheel from the bike. Spin the gears. If only the gears seem to spin and a significant area inside the gears does not spin it is a freewheel. On a freehub, everything but the axle will spin and there will be a pretty obvious lock ring holding the smallest cog in place.
So a more or less complete upgrade would cost less than $200 plus a 9-speed chain. Now you may have compatibility issues with your current crankset if you go from 8 to 9 because of the spacing. Might work, might not.
Hope this added to your confusion.
12-18-01, 01:33 PM
I called my LBS, here's what he said (I'm rounding numbers up)
Hub 9spd $25
Sprockets rear $40
Derailer $50 Deore LX
new speed shifters set with cables $60
Labor to do all $20
Not too bad, I really like the bike, and it's not so flashy that it screams steal me when I park it. One thing I'm going to do after work is put on some wellgo pedals with straps $22. My pedals are plastic.
It works fine now, will it make a noticable difference?
12-18-01, 03:15 PM
If it works fine now I'd ride it 'til something breaks. I'm not sure the described upgrade will give you a significant improvement.
12-19-01, 06:59 AM
The Acera X drivetrain was already better than most more expensive bikes that the LBS had but they had a crank off of a rock hopper and good pedals with built in straps. This will give me the additional top end I needed on the downhills (bigger front sprocket), and more power on the hills with the straps on the pedals. I'm happy, total bill about $75. The downside, I have to drive today, can't pick it up until tonight.
12-19-01, 07:33 AM
If I get upgrade fever and decide to replace bits piecemeal (hey this buying bike bits is getting addictive :D) I'm probably going to have to go from 7sp to 9sp. Forgive my ignorance, but does this generally mean a similar bottom and top with closer gearing in between or gearing the same difference apart but with a higher top and lower bottom?
I'm currently running SRAM ESP 3.0 shifters, and rear derailleur (I'm quite happy with these) and a Shimano front mech which seems to be the weakest part in terms of performance - I get next to no mis-shifts on the rear but the front isn't anywhere near as reliable (is this just the nature of the front?).
Originally posted by Richard D
... I'm probably going to have to go from 7sp to 9sp. Forgive my ignorance, but does this generally mean a similar bottom and top with closer gearing in between or gearing the same difference apart but with a higher top and lower bottom?
... a Shimano front mech which seems to be the weakest part in terms of performance - I get next to no mis-shifts on the rear but the front isn't anywhere near as reliable (is this just the nature of the front?).
1) Whether to obtain a higher high, a lower low, both, or neither during the 7-to-9 upgrade is entirely up to you. If you are happy with your current gear range, go for the closer-ratio progression. [For a road bike, low 40s (e.g. 42/26 or 39/24) to high 90s (e.g. 48/13 or 50/14) works well for me.]
2) The rear mech will almost always work better than the front, which is arguably the most primitive part of the drivetrain. The rear guides the slack lower portion of the chain across small steps, whereas the front drags the tensioned upper lnks across much larger steps. (This, and the fact that I'm a retrogrouch, is why I still use half-step or one-and-a-half-step gearing, with 3- or 8-tooth jumps in front, rather than the more modern crossover patterns, with their 10- to 14-tooth steps.)
12-19-01, 10:54 AM
The most cost-effective upgrade are tyres. Good ones will let you go faster.
Next, a track pump will help you keep your tyres pumped up hard. Dont delay, get one.
Brake blocks can be pretty variable, and it pays to get good ones.
Next come cables.
Switching to TA chainrings and Sachs chain with a good lube will help the transmission last longer.
Upgrade your hub bearings to ISO grade 25 balls, and upgrade your cones to XT grade (of the the same size!!), and your wheels will spin a little better for longer.
I dont think derailleurs make a huge difference to gear changing. More expensive ones are lighter and will last longer, but cheaper Shimano mechs work pretty well. The front mech is definately the last thing you should upgrade.
7 to 9 gearing will make little difference in practice.
Generally, upgrading a low-end bike is not cost effective. Commuting on a high-end bike is not very smart, unless you can lock it indoors.
Never skimp on tool quality. Ive regretted buying stupid bendy cone wrenches. You'll only have to replace them with good ones later. Go for Park or other good name.
12-20-01, 12:05 PM
Tried out the new crank and sprockets, much more high end and smoother middle gearing. Just what I needed. I will test the lower end on the way home. Pedals are a big improvement. Built in straps help to get that 360 degree power. A big improvement on a low end bike. I rode back the 3 miles to work after driving home at lunch, didn't even work up a sweat. The stock gearing was too low on the high end.
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