new cassette- do i need a new chain?

i have a similar dilemma replaced my chain found it was jumping on rear cogs under stress so replaced cassette. now find it still seems to jump/skip under stress out of the saddle riding but only on the middle ring(i run a triple). should i replace the middle chainring?

Not suggesting for 1 minute you need to change your chain every 70 miles.

Fact of the matter is the dudes chain is now too short.
If your not mechanically minded and dont have the proper tools then adding a couple of links on to a chain might not be particularly easy and could have disastrous consequences. you could always buy some new links and pay someone else to do it, then the whole argument about cost goes out the window.

Is replacing the chain really so ridiculous?

Just seen this, I'm F****D then, I've nearly put 70 miles on my trike and it runs 3 10 speed SRAM's.....Better get new ones.

WISE UP, there is NO NEED for a new chain at all, listen to us guys with large post counts, we seem to know what we are talking about

No need for a new chain after 70 miles. Use the 20 quid or so for a meal or a few pints tonight. Everyone else wind your necks in!

+1 for bikecellar's comment. Do you guys pump up your tyres or just buy new wheels when the pressure gets too low?

Do keep on top of it though, I cost myself a couple of chainrings this year because I didn't change my chain. Still that's only £100 or so compared to £3000 for a new chain every 70 miles.

YOU DO NOT NEED A NEW CHAIN JUST TWO EXTRA LINKS, ANYONE SUGGESTING OTHERWISE DOES NOT KNOW WHAT THEY ARE TALKING ABOUT, IF 70MLS = NEW CHAIN I WOULD BE GOING THROUGH 4 CHAINS PER WEEK

After 70 miles i can't see the necessity for a new chain...

For the sake of less than 20 quid i would just replace it.

After 70 miles? - Unless it was 70 miles of steep hills and/or particularly dirty weather I doubt it.

However its a good idea to have a spare chain ready to go for when it does need replacing - if you have another chain handy you are far more likely to replace it when it reaches its wear limits. (A chain checker in one's toolbox is always a good idea)

Its a pretty good idea too to keep chains and cassettes as matched pairs so depending on what you plan to do with your old cassette it could be prudent to keep those two together if you ever want to re-fit them. In the meantime if the new chain exceeds its wear limit, the old one should serve as a good replacement, though it would need a few extra links adding, but you'd have them left over from the new chain I would imagine.

If you want to try the old chain with the new cassette, you'll find out very quickly if it works or not - it would sit awkwardly on the cogs and skip under hard, jerky pedaling (like out of the saddle), particularly the smaller ones where there are less teeth are in contact with the chain. It would be very wasteful to throw the old chain away though - there's probably a couple of thousand miles left in it yet.

In an ideal world yes to a new chain.

New chain. Absolutely.