Shimano HG70 7 speed Cassette

[Manonabike]

I wonder if I can replace a 7 speed cassette with an 8 speed cassette and if so, what adjustments would I need to do?

And before you ask why I wish to do that then the reason is that I cannot find 13 -30 shimano HG70 7 speed cassette.

Thanks

 

[andrew-the-tortoise]

Depends on the hub freewheel part; if it is eight speed then yes. [The original seven speed cassette would have been spaced off at the back].

 

[Manonabike]

The hub is an original 7 speed

What would I need to change to upgrade to 8 or even 9 speed? Any idea on the cost to upgrade?

It's an old bike, 18 years old, but a favourite of mine and still in excellent condition - based on a 531 frame.

 

[MartinC]

If you did this you'd need 8 speed shifters.

A 7 speed freewheel is narrower than an 8 speed. You can mount a 7 speed cassette on an 8 speed freewheel by putting a spacer behind the cassette. If your cassette has a spacer behind then it's on an 8 speed freewheel and you can mount an 8 speed cassette.

Alternatively these people have a variety of HG70 7 speed sprockets so you could replace the worn ones. http://www.roseversand.de/output/co...=1&marke=-1&bereich=285&warenbereich=&ebene=3

Another alternative. 8 sprockets and spacers from a 9 speed cassette will fit on a 7 speed freewheel. Choose a 9 speed cassette and discard one sprocket, fit 9 speed shifters and you've got an 8 speed transmission.

 

[Manonabike]

If you did this you'd need 8 speed shifters.

A 7 speed freewheel is narrower than an 8 speed. You can mount a 7 speed cassette on an 8 speed freewheel by putting a spacer behind the cassette. If your cassette has a spacer behind then it's on an 8 speed freewheel and you can mount an 8 speed cassette.

Alternatively these people have a variety of HG70 7 speed sprockets so you could replace the worn ones. http://www.roseversand.de/output/co...=1&marke=-1&bereich=285&warenbereich=&ebene=3

Another alternative. 8 sprockets and spacers from a 9 speed cassette will fit on a 7 speed freewheel. Choose a 9 speed cassette and discard one sprocket, fit 9 speed shifters and you've got an 8 speed transmission.

That is a clever alternative - thanks for that.

The cassette is all in one piece, I changed it once before for a "Shimano Cassettes - Road 105 Cassette 7 Speed HG70. Size 13-30"

Appreciated all advise given.

 

[TheDoctor]

Would either of these fit the bill?
12-32 7 speed SRAM from CRC or 12-32 Suntour from Byercycles
Both Shimano compatible. I can vouch for the SRAM one - I use one myself and it's good.

 

[Manonabike]

Would either of these fit the bill?
12-32 7 speed SRAM from CRC or 12-32 Suntour from Byercycles
Both Shimano compatible. I can vouch for the SRAM one - I use one myself and it's good.

This is getting better and better I'm so glad that I posted my question.

I have no problem with SRAM, I actually have SRAM chain and very happy with it....

Now, would the SRAM cassette fit my hub?

I remember searching the Sheldom website for information on what type of cassette I needed to buy and I found the information on this page freehub

There is an image of a freehub like mine just above the following text:
"Shimano Cassette Freehub, showing characteristic bulge on the right side of the body"

 

[TheDoctor]

Yes it would. If a Shimano 7 speed cassette went on, then the SRAM will. And the Suntour one, for that matter.

 

[Manonabike]

Yes it would. If a Shimano 7 speed cassette went on, then the SRAM will. And the Suntour one, for that matter.

Thanks for that..... I ordered one already

 

[MrRidley]

I wonder if I can replace a 7 speed cassette with an 8 speed cassette and if so, what adjustments would I need to do?

And before you ask why I wish to do that then the reason is that I cannot find 13 -30 shimano HG70 7 speed cassette.

Thanks

Evans cyles http://www.evanscycles.com/products...oogle&utm_medium=froogle&utm_campaign=froogle

 

[Manonabike]

Evans cyles http://www.evanscycles.com/products...oogle&utm_medium=froogle&utm_campaign=froogle

I saw that but the 13 -30 has been discontinued - they only do a 13 - 28.

I have already ordered a SRAM cassette but thanks anyway.

 

[MartinC]

The cassette is all in one piece,

I know that you've ordered a SRAM cassette but for the future - it may look like the cassette is all one part but often they're individual sprockest and spacers held together with rivetted or screwed pins that you can easily remove. Some higher range cassettes may have the bigger sprockets grouped on a carrier but if you buy spare sprockets for the right model of cassette (HG70 etc.) then they should fit. The sprockets have a position on the cassette (denoted by a letter) which you need to take into account - Shimano techdocs on the net will give the detail.

 

[youngoldbloke]

- and then there is http://www.rutlandcycling.com/13089/Shimano-HG70-7-speed-cassette.html
- yes I know you've ordered the SRAM one, but there are others who might be interested - like myself - the proud owner of a 16 year old Peugeot 525 Comp 14 speed, which may need a new cassette soon.

 

[Manonabike]

I know that you've ordered a SRAM cassette but for the future - it may look like the cassette is all one part but often they're individual sprockest and spacers held together with rivetted or screwed pins that you can easily remove. Some higher range cassettes may have the bigger sprockets grouped on a carrier but if you buy spare sprockets for the right model of cassette (HG70 etc.) then they should fit. The sprockets have a position on the cassette (denoted by a letter) which you need to take into account - Shimano techdocs on the net will give the detail.

Hi and thanks for the info. I didn't realise that the cassette has individual sprockets.... I will look into it.

The SRAM cassette is here but I'm yet to put it on..... this cassette's biggest sprocket has 32 teeth and my current cassette has 30.... it does look, by just looking at the cassette against the old cassette, that the 32 might be too big but I'm not an expert so my question is how do I find out if this new cassette will fit, without obviously attempting to fit the new cassette?


youngoldbloke, the link leads to an out of stock item but thanks anyway.

 

[craigwend]

A bit late but...

http://www.sjscycles.co.uk/category-Cassettes--7-Speed-72.htm

I'll have the same problem with my galaxy next time, but have decided to stick with 7