bobk544

Hello,

I have an older 7300 Trek hybrid that looks like it needs new chainrings, cassettes and chain.

I'm wondering if it will be worth fixing up or should i just go to performance and get a new bike for around $225.00, figuring the new parts would probably be around $100.00?

Thanks for any insights!
BobK

Retro Grouch 

So how do you feel about the bike otherwise?

Here's the question: If somebody else owned your Trek only it had a brand new cassette, chainrings and chain; would you be willing to pay $100.00 to buy it?

bobk544

That's a good way to look at it Retro!

Yes if i knew those components were new then i probably would pay 100 and i forgot that i also put a brand new double hull wheel on it right before i stopped riding it, so that's a consideration too.

But i quess i'm assuming that i will be able to figure out how to put those parts on the bike, never done it before and i quess i will need to buy the tools as well, so that's another factor i quess.

The bike shop said they would charge 180 and i quess that's what's making me think about just buying a new lesser quality bike from performance for 225, figuring the less quality of today may be equivalent to the Trek quality of 10 years ago maybe?

And I think i can do the work but after trying to find the parts, i'm realizing that there's a pretty good chance that i could end up buying the wrong parts as there isn't a clear cut cross reference to the old parts from what i can see on the web, so the cost of the tools and the possibility of buying the wrong components has me hesitating as well.

Thanks again!
BobK

Retro Grouch 

Those aren't difficult jobs - maybe a 3 on a 1 to 10 scale of difficulty. Cassette lock ring remover, chain whip, chain breaker and a 5mm allen wrench are all of the tools that you'll need. Offsetting the cost of the tools is the education and the satisfaction that you'll get from doing it yourself. If they don't look "pointy", there's a good chance that you don't need chainrings. They'll generally outlive several cassettes.

The trade off - that $225.00 Performance bike, can't be very satisfying.

bobk544

Yes Retro you are absolutely right about the satisfaction factor, that is something to factor in for sure and i can reuse the tools on my other newer 7300.

I just went out and counted the larger chainring count of 48 teeth and in the process noticed that the #2chainring has almost 1/4 of it's teeth missing! can't imagine how i did that but i never remember abusing the gears at any time, but it's been awhile since i've ridden it.

So Retro, you are saying if the chainring teeth aren't pointed to much, they may be ok?.....that's good news cos the chainrings seem to be the most costly replacement parts, so maybe i can get away with just replacing the #2 gear then and i think i can get a cassette set from nashbar around 30 bucks.

Hmmmm quess i will look into this further and if i can keep the cost to around 100 i think i will give it a go....like you said there is definitely a satisfaction factor to consider in the equation and i also have a newer 7300 that i will eventually need to maintain as well!

Thanks again Retro!
BobK

Joshua A.C. New

Was the 7300 made in 1998? I thought it was more recent than that.

I bought a 7300 frame on Ebay and made a bike out of it that I really like. Maybe take some pics, particularly of the drive train, but pics of the whole bike are helpful, too.

Retro's right: this isn't a hard thing to do yourself and you'll learn some really fundamental stuff.

Sixty Fiver

My 1999 Trek 7500 after rebuilding... I love this bike and think I built a Trek Portland before there was a Portland.

I replaced the drive train parts because I wanted a stronger bike... the complete M440 crank and chain rings cost me $45.00 and I run it as a double (no granny), the 8 speed Sun Race cassette cost $10.00, the SRAM chain was $20.00.

So I paid $75.00 for parts and did all my own work which took very little time at all and is something I teach people to do all the time.

bobk544

Actually Johhua i'm not sure when i actually bought my older 7300 but it may have been around 1998/9 when i got back from Colorado, but i do notice a big difference between the older and newer frames of course, i like the older version cos it doesn't have the front shock, so it's a bit lighter and i want to experiment with some 28c tires just for local errands and trips to the metro stop ect.

I love my newer 7300 and am riding it to work a few times and week and do long jaunts on the weekends, and the bontrager wheels seem to be holding up alot better than i thought they would so that's very encouraging!

Thanks for the assistance all!

BobK

bobk544

Yes S.Fiver i know what you mean, Trek is very safe and reliable and at 230lbs + 10to30lbs of gear/water ect usually it keeps on running fine and now i clean the chain and gears on a weekly basis.

Gee if i could find a crankset and chainrings for 50 to 60 i'd be raring to go, but finding the parts seems to be a real challenge so far!

So my plan now then is to use my newer 7300 for the metro runs for now and start scouring around for parts and tools, i just did a google on a label i found on the large chainring and it says Shamano Dual 515, but i'm not getting alot of finds on that specification.

Maybe i will head over to Spokes in Vienna VA today and see what they can order and how much, but i know it won't be cheap, but since i think i can get the cassette for 30 or so i quess i'd be willing to pay up to 70 for the chainrings, but to get the whole crankset for that price would be a real deal looks like!

Anyway i used to think that the heavier bikes were a disadvantage, but now i realize that it's a better workout and if i ever decide to get a road bike like a 7500 or up, it'l probably be like a rocket sled compared to the 7300 and i'm looking forward to that someday!

Thanks again all!
BobK

Retro Grouch 

Examine your chainring more carefully. My guess is you'll find what looks like damaged teeth exactly opposite one another. If that's the case, you're looking at "shifting aids" that are designed into the chainring.

cudak888 

Is there anything directly perceptible with the machine whilst one rides it that would indicate the requirement of replacing parts? Or was this something indicated to you by your local shop as a side note?

-Kurt

bobk544

Well when i was riding it the chain would skip under load, so i took it took a local guy who put on new chain on it for me and i quess we left in too many links or something and i could barely make it home, maybe that's when i chewed up those #2 teeth, so i made it worse by puttin the new chain on it as it would only skip under a steep hill load.

Hmmmmm maybe what i should do then is just replace that #2 and see how that helps as i'm not going to use this bike for my main ride and that way i can replace it as needed instead of assuming that everything needs replacing?

I quess i figured i'd need to replace everything after reading that when your chain is streched to a certaini point that it has probably messed up the teeth, but maybe since i have a new chain now i can just try replacing #2.

Also when i took it to the LBS they said everything needs replacing and it probably does if it was going to be my main set of wheels, but since it's just a short hop to the store/metro bike, maybe i can piece meal it along!

Thanks all!

Sixty Fiver

My old 7500 was not originally a road bike and came as a hybrid model with a bunch of heavy parts like an adjustable stem, riser bars, and suspension seat post... it is actually a fairly light bike and the stiffness in the frame is really offset by the 700:35 tyres I run and the ride is very smooth... touring / commuter bikes tend to weigh more due to their stronger components and this is a good thing.

I have often said that if I could only have one bike, this would be it as it can handle pretty much anything I throw at it.

cudak888 

At this point, I would have the cassette changed only - unless the new chain was positively damaged after installation. If the latter is so, I dare say whoever did the work should compensate you in some form or another for the brand-new, wrecked chain - after all, it was with their recommendation that you replace chain only, and their negligence that put you in a situation of riding with worn cassette. I doubt if any chain skipping would have caused damage to the chain though. Not sure what you mean by "#2."

I would be surprised if you have ridden it hard enough to eat up the chainrings, although it is possible. Don't replace any of them (likely a three-piece unit though) unless absolutely necessary.

Have that cassette replaced, then see about the results. Also, if your riding habits take you primarily on the flats, take the opportunity to get a cassette with a narrower range (being from flat country, I advise this to most folks who have to replace stock, wide-range cassettes). If otherwise, stick with the usual gearing.

-Kurt

bobk544

Hello,

I found this crankset at Jenson and the salesman asked if i had a "square-taper" bottom bracket, so when i unscrewed the crank bolt i do see a square looking axle thru the bracket and i also see that the new part has a "DUAL" decal on it and my current gear has that "DUAL" label as well. The teeth counts are the same as well 48, 38, 28.

https://www.jensonusa.com/store/produ...+Crankset.aspx

Is this too good to be true or am i getting lucky for a change?

Also on that chain fubar, i tried to cut corners and took it to a person on craigslist who works on bikes more like a hobby i quess and he put the chain on for 15, but i think i remember him mumbling under his breath something like "hmmmmmm wonder if i got the link count right", but he lives on the top of this huge hill near Glen Echo and by the time i got to the bottom and put a load on it it skipped all over the place so i could only put it in 1 gear all the way home, about 20 miles, man that was touch and go, but i think i really mangled the chain trying to find that 1 gear combo that traversed the chain between high and low to make up for that extra link!

But wow if this crankset will fit i'm going to be a happy biker fixer upper!

Thanks again for any insights!
BobK

DDYTDY

bobk, I don't know where you live but a lot of cities have bike co-ops where you can learn how to do things and use tools and stuff.

To change cranks you'll need a crank puller......

You might want to explore this sight:

https://sheldonbrown.com/home.html

Joshua A.C. New

Bob, that crankset should work fine for you. It's kinda low-end (you won't be able to change chainrings without changing the whole thing, and it probably weighs a ton), but it'll last a good while, is my guess.

The cassette is at least as critical. If indeed it's as worn as it sounds, you should replace it. Get another with the same number of cogs as your current one (probably 8?). That way, you won't have to jigger with the rest of the shifting.

Here's my 7300, btw. (click through to see more pics)

cudak888 

Why do you want to attack the (possible) chainring problem before the rear cassette? The cassette, from what you have said, most definitely needs to be replaced, and is of far more concern then the chainrings, which could just as well be fully functional in their present state.

-Kurt

bobk544

Wow those are some interesting mods to your 7300 looks like a road bike now!

Regarding the cassette, i must have mistated, it was the #2 or middle chainring of 3 that is missing about 6 teeth! can't imagine when i did that cos i'm fairly ginger with the geers, must have been that chain fubar event but i didn't sound like it was chewing it up!

Found this great site called bike pedia and i'm pretty sure i have the 1999 Trek 7300:

https://www.bikepedia.com/QuickBike/B...7300&Type=bike

and it has a Shimano Nexave crankset with a 122.5 spindle 48 38 28 so now i can narrow it down a bit more hopefully.

Thanks again all for help, going to scour around a bit more and see if i can find a crankset with removable chainrings, otherwise i'll just get the riveted kind!

BobK

chas0039

I cannot be sure without seeing your chainring, but be aware that a lot of chainrings look worn down when new due to the design to allow it to jump to the next ring. If you see a pattern in the wear and it is regular you might be looking at a design.

Just a thought.

cudak888 

Correct, A.K.A. Shimano Superglide:



-Kurt

gascostalot

I recently brought a 15 year old Trek M-T 720. While I am mechanically inclined, I had no idea what goes into a bike.

Trust me, rebuilding a bike is simple. The hardest thing about rebuilding a bike is falling into the 'upgrade treamill' were you vast amount of money on high end parts that would be overkill for the kind of riding you're doing.

The best thing about rebuilding a bike is that the bike will be yours. You will know all the little details about the bike, and your relationship with the bike will be almost intimate.

bobk544

Thanks for the super excellent photo! i see what you'all are talking about, at first glance it looks like the gears are bent out of shape, but i just checked the 99 again and yes the gears are really truely chewed up unfortuneately!

Thanks again all for the great help and advise!

BobK

Sixty Fiver

A better pic of the bike when it's rigged for my epic commute...

The double (32/42) gives me 27 to 103 gear inches with the 11-32 cassette which allows the bike to climb walls and cruise at a pretty high speed... I might run a triple up front (could add a granny) if I undertake any really epic journeys where crossing mountains is involved.

The cross bars are so much better than the flat bars it came with as they offer a better aero positon and more hand positions for long rides... with the quill stem I can also raise the bars pretty easily.

After paying $110.00 for the bike (it was in great shape) I may have spent a few hundred dollars building it up into what is a pretty exceptional bike... the hardest thing was waiting for some bar cons to show up at the bike co-op as these were a musty have.

DDYTDY

SF you got the coolest bikes!