Need to change chainset and gear cassette. What do I need to know before I buy?

[Mr. Whippy]

My old Mongoose 21 spd Crossway 450 (7 in the cassette, triple crankset) has a lot of broken teeth now.  I want to replace them (and new chain).  I doubt every triple crankset and seven gear cluster will fit this bike.  What do I need to know before I buy?

btw, this isn't going to be a $$$$ set.  I'm looking for a basic set.

[AimlessWanderer]

Nate, I cocked up recently and ordered a seven-speed rear cassette that wouldn't fit my bike  I took it back into the same bike shop for them to fit (I didn't have the tools), and they told me I'd ordered one that was incompatible. They helped me choose something compatible, gave me some discount on the replacement as it was more expensive, and I just had to pay the difference (£0.50  ) ... and then they fitted it for me free of charge too. This wasn't "mates rates" either, just a local bike shop who doesn't know me from the next man. I asked them for a rear reflector as I wanted one to mount on the frame rather than seat post, and he threw that in for free too 

Personally, I think that if you're not 100% sure what you need, I'd just take it to a store and get them to sort it

[Higgins617]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

[Mr. Whippy]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

Your post makes total sense.  Back in the 1980's I did a few swaps, but there were less variations back then.  Yep.  It has AceraX now.

This is what is listed for Bottom bracket:

Bottom Bracket: YST, 110 mm spindle

Does that tell me what I need to know?

[Higgins617]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

Your post makes total sense.  Back in the 1980's I did a few swaps, but there were less variations back then.  Yep.  It has AceraX now.

This is what is listed for Bottom bracket:

Bottom Bracket: YST, 110 mm spindle

Does that tell me what I need to know?

I'm 99% sure that's a square taper. All that means is that there's a square hole in the crank for it to fit over.

Amazon says the Shimano Altus crank with the same tooth count is $32 or so.

The cassette I was looking at was the Shimano HG50 and your bike has an 11-28 tooth range.

Are you planning to do it yourself? Or just making sure you don't get smurfed over if you bring it in?

[Mr. Whippy]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

Your post makes total sense.  Back in the 1980's I did a few swaps, but there were less variations back then.  Yep.  It has AceraX now.

This is what is listed for Bottom bracket:

Bottom Bracket: YST, 110 mm spindle

Does that tell me what I need to know?

I'm 99% sure that's a square taper. All that means is that there's a square hole in the crank for it to fit over.

Amazon says the Shimano Altus crank with the same tooth count is $32 or so.

The cassette I was looking at was the Shimano HG50 and your bike has an 11-28 tooth range.

Are you planning to do it yourself? Or just making sure you don't get smurfed over if you bring it in?

Do it myself. I have all the tools and have done both of these processes several times before (back in the 80's on a Raleigh).

Edit to add:  I ended up recycling my old Raleigh because the frame offset had become obsolete.  I could have tried rebuilding the cassette, but honestly, it was just a midrange Raleigh back in 1980. 

[Higgins617]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

Your post makes total sense.  Back in the 1980's I did a few swaps, but there were less variations back then.  Yep.  It has AceraX now.

This is what is listed for Bottom bracket:

Bottom Bracket: YST, 110 mm spindle

Does that tell me what I need to know?

I'm 99% sure that's a square taper. All that means is that there's a square hole in the crank for it to fit over.

Amazon says the Shimano Altus crank with the same tooth count is $32 or so.

The cassette I was looking at was the Shimano HG50 and your bike has an 11-28 tooth range.

Are you planning to do it yourself? Or just making sure you don't get smurfed over if you bring it in?

Do it myself. I have all the tools and have done both of these processes several times before (back in the 80's on a Raleigh).

Edit to add:  I ended up recycling my old Raleigh because the frame offset had become obsolete.  I could have tried rebuilding the cassette, but honestly, it was just a midrange Raleigh back in 1980. 

GOOD! Nothing like wrenching on your own bikes, I love it. Do you already have the Shimano cassette tool? I'm not sure what year your bike is so I don't know what hub it has. If it's just the generic Shimano hubs it'll be easy to get a cassette for it.

[Mr. Whippy]

I've done this many times, I have a habit of wearing them out a bit fast

I just did a quick search and it looks like your bike is all Shimano equipment, which I prefer anyway. The cassette itself will likely run you no more than 25 bucks and that's for one that'll likely be more than you need.

Most of the cost will be labor, a decent 7 speed cassette and chain will likely be sub-40 bucks(going by the prices on jensonusa where I order parts)

The cranks will depend on the type of bottom bracket you have, but I'm willing to bet its a square taper. A triple for that bottom bracket will likely be another 35ish. I would say look at the Shimano Acera or Altus. The Tourney series is something I could just never recommend to someone I like

If this isn't clear please feel free to let me know,I'd love to help

Your post makes total sense.  Back in the 1980's I did a few swaps, but there were less variations back then.  Yep.  It has AceraX now.

This is what is listed for Bottom bracket:

Bottom Bracket: YST, 110 mm spindle

Does that tell me what I need to know?

I'm 99% sure that's a square taper. All that means is that there's a square hole in the crank for it to fit over.

Amazon says the Shimano Altus crank with the same tooth count is $32 or so.

The cassette I was looking at was the Shimano HG50 and your bike has an 11-28 tooth range.

Are you planning to do it yourself? Or just making sure you don't get smurfed over if you bring it in?

Do it myself. I have all the tools and have done both of these processes several times before (back in the 80's on a Raleigh).

Edit to add:  I ended up recycling my old Raleigh because the frame offset had become obsolete.  I could have tried rebuilding the cassette, but honestly, it was just a midrange Raleigh back in 1980. 

GOOD! Nothing like wrenching on your own bikes, I love it. Do you already have the Shimano cassette tool? I'm not sure what year your bike is so I don't know what hub it has. If it's just the generic Shimano hubs it'll be easy to get a cassette for it.

1996.

[Higgins617]

The only year the hubs aren't listed for

[Mr. Whippy]

The only year the hubs aren't listed for

I'm sure it's the same as the 1995.  (AceraX).  The cranks, and brakeset are all AceraX.  I'd be surprised if it wasn't a matched set. 

[Higgins617]

The only year the hubs aren't listed for

I'm sure it's the same as the 1995.  (AceraX).  The cranks, and brakeset are all AceraX.  I'd be surprised if it wasn't a matched set. 

Agreed, I'd just hate to speculate and tell you the wrong thing though.

[Mr. Whippy]

If I swapped the whole groupset, could I directly swap to Alivio?  (that is, is Alivio groupset compatible with Acera? )

[Higgins617]

If I swapped the whole groupset, could I directly swap to Alivio?  (that is, is Alivio groupset compatible with Acera? )

The new Alivio stuff isn't 7 speed compatible I don't think. The last Alivio offered in a 7 speed setup is the M410 model rear derailleur. Jenson has the M410 derailleur for sale still for 35 bucks, the cranks though look like they all may need bottom bracket spindle lengths longer than 110mm, except the one that costs 135 bucks

How bad is the Crank?

[Mr. Whippy]

If I swapped the whole groupset, could I directly swap to Alivio?  (that is, is Alivio groupset compatible with Acera? )

The new Alivio stuff isn't 7 speed compatible I don't think. The last Alivio offered in a 7 speed setup is the M410 model rear derailleur. Jenson has the M410 derailleur for sale still for 35 bucks, the cranks though look like they all may need bottom bracket spindle lengths longer than 110mm, except the one that costs 135 bucks

How bad is the Crank?

So I guess what you're saying is, I have to stay with a 7 spd cassette because of the frame offset?  The crankset and cassette both have many broken/worn down teeth.  It's gotten to the point that there's signficant chain slippage when climbing (and pesky chaindrops).

I should have replaced them a few years ago, but I was able to manage.   

[Higgins617]

If I swapped the whole groupset, could I directly swap to Alivio?  (that is, is Alivio groupset compatible with Acera? )

The new Alivio stuff isn't 7 speed compatible I don't think. The last Alivio offered in a 7 speed setup is the M410 model rear derailleur. Jenson has the M410 derailleur for sale still for 35 bucks, the cranks though look like they all may need bottom bracket spindle lengths longer than 110mm, except the one that costs 135 bucks

How bad is the Crank?

So I guess what you're saying is, I have to stay with a 7 spd cassette because of the frame offset?  The crankset and cassette both have many broken/worn down teeth.  It's gotten to the point that there's signficant chain slippage when climbing (and pesky chaindrops).

I should have replaced them a few years ago, but I was able to manage.   

The 7 speed hub wont fit an 8 or 9 speed cassette, 8 and 9 are typically interchangeable, but 7 speed is like the forgotten child. So if you got a new wheelset that wouldn't be an issue, but then you'd run into the spacing issue you mentioned. I've pulled chain stays apart to have a wider hub fit, but I wouldn't exactly recommend that.

[Mr. Whippy]

It looks like 7 spd are still available, so I'll just go with a direct replacement. 

[Higgins617]

It looks like 7 spd are still available, so I'll just go with a direct replacement. 

Good luck! Sorry I couldn't be of more assistance . Let me know if there's anything else I can do.

[Zed]

Looks like your sorted here mr W  its all complicated stuff and so glad all my bikes use shimanos hyperglide ,the splined tool is pretty cheap and easy too use,i dont think ive even got the older tool anymore,good luck with removing it 

[Mr. Whippy]

It looks like 7 spd are still available, so I'll just go with a direct replacement. 

Good luck! Sorry I couldn't be of more assistance . Let me know if there's anything else I can do.

Actually, you answered the exact questions I had! Thanks.  I'm running into the same problem I had with my Raleigh--obsolescence (unless you want to go crazy restoring).  If I can get back to the original configuration, I'm perfectly happy.  Thanks again.