Tonearm/cartridge weight considerations

I have just decided to dig up my old vinyl collection that has been waiting for better days since mid-80s. Bought a turntable (Thorens 124) without tonearm. I have Shure V15V-MR cartridge. Started to look around for an appropriate tonearm and found out that the tonearm/cartridge issue has grown into a science. Now I am confused about this tonearm/cartridge weight issue. Could enyone illuminate me about this issue, mainly covering the following questions:
1) they speak of light/medium/heavy arms, so what are the figures for those weight categories?
2) are there weight categories for for cartridges and if yes - where my SHure V15V-MR fits?
3) does a light tonearm needs a light cartridge, or is it totally opposite - a light tonearm needs a heavier cartridge and vice-versa?
4) what can go wrong if the rules of tonearm/cartridge weight are ignored?
Thank you!
Welcome to A'gon! Someone may pop up with some direct answers, but you can probably find them by doing a search. You want to look for references to effective mass, compliance, and tonearm resonance. These topics have been covered extensively here.


Thank you for reply. I did some Audiogon archive search, however here in Audiogon most of the relevant topics are about specific arms and specific cartridges whereas my question was more general, perhaps even more theoretical. What I am looking for are general considerations for combining a cartridge with an arm. I do not care much about question "what cartridge is the best for SME V" or anything like that. I do no believe in "the best for all times" because there can be many combinations with different results, many of them good. My worries are not to make some stupid things while experimenting and searching. Did not find much information on this one. However, while doing the search I found a good reference to Van Den Hul homepage where they have quite extensive FAQ in phono section. Some useful information can be found there at least to start with.
Read this link.
Actually you are trying to match the effective mass(different from weight) of the tonearm and compliance of the cartridge. You've chosen a very easy to match cartridge in the Shure, being a medium compliance piece. Look at this page for more insights-(
I would consider the Shure a high not medium compliance cartridge.

At 25 it is far above what generally is accepted medium i.e. 12-17.
Thank you for the advice. Now I have to do the rest of the homework :)
I suppose I missed the fact that there was no, "X" in his designation. The V15VX-MR has a compliance of 15. My bad! In that case: look for a fairly low effective mass arm. My Denon 103D's compliance is 30, and works wonderfully with my old Magnepan Unitrac I.
Actually the published spec for a Denon 103-D in 1977 was 12cu which makes it a medium, not high, compliance cartridge. See this link:

Values of 10cu-20cu are considered medium compliance, 25cu high, and 35cu very high.

Hope that helps.
I don't remember saying my DL-103D was still stock. It now sports a van den Hul type I stylus, a boron cantilever and new rubber compliance. Tested as stated.
>>I don't remember saying my DL-103D was still stock<<

That's generally understood with cartridges; perhaps not electronics though.

New rubber, stylus, and cantilever aside, the significant increase in compliance over the stock specifications is doubtful. That's a big jump.
There are a lot of modded/rebuilt cartridges out here, just as there are a lot of modded electronics. I suppose: a lot of people that aren't aware of the practice as well. The rubber cantilever suspension makes all the difference in the "compliance" of the cartridge. Change the density of the rubber, you've changed the compliance of the cartridge.
Not to the extent that you have indicated.
Thank you.
And now pontification trumps experience? How tedious this has become!