Rupes 15 vs Rupes 21 w/5" backing plate

[jarred767]

Rupes 21 with the KB washer mod and 5" backing plate with 5.5" pads is my main tool for all correction jobs, and I love it! I have the 6" BP too, but going back and forth is cumbersome to say the least, so I rarely use the 6". The 21 is a great tool!

[feslope]

According to Todd Helme, what the 15 lacks in orbit it makes up for in faster opms. He further says that because of the faster sopeed of the 15 the differences in correction speed between the 15 and the 21 is very little. Science tells me that the previous being true would result in the 21 running a 6" pad would most certainly result in less correction speed than the 15 running the 6'" pad.

When I first got my 15 it came with the 7" pads by mistake, it was barely able to turn them let alone do effective correction. I doubt running the 6" plate with the 7" pads on the 15 would have made any difference. IMHO and experience, 7" pads on the 15 is a bad idea.

Sounds to me like the 21 is a geared down 15 power and speed wise. If you really need both throws you should buy both polishers. If speed is not a factor get the 21 with both size plates.

I look forward to your response.

[expdetailing]

Well, since I started this thread, I purchased the Rupes 21, 15 and Flex 3401. For one-steps, I soley rely on the Flex. When performing a two-step, I use the Flex for the first step, then try to use one of the Rupes for the second step.
The reason I use the Flex first is because it's guaranteed to correct most of the vehicle, whereas the Rupes can stall on certain panels. Also, I couldn't find a good combination of cutting compound that worked well with the 21. Compounding with the 21 led to a lot of dusting. I had less dusting with the Flex.
The reason I use the Rupes on the 2nd step is because I find the Rupes easier on my ears and hands/wrists, a little smoother, and more pleasant to use, and doesn't seem to dust as bad when using a medium-to-fine polish with a polishing pad.
I had a friend call the Flex the "sawzall" (spelling?) of polishers, and I think that's a decent description. It's tough, durable, cuts well, and doesn't play around. It gets the job done the first time, and every time.
With that said if I'm performing a second-step, I'm looking forward to using the Rupes by then.
By the way, I used the 5" BP on the 21 and compared it to the 15. I found that I slightly preferred the 21 w/5" BP slightly over the 15. Not by much though. The 15 is an excellent choice.
I've yet to switch the 5" off the 21 in exchange to put the 6" BP back on. I prefer it this way.
Thank you to all who have responded to this thread to make it interesting.

[feslope]

By the way, I used the 5" BP on the 21 and compared it to the 15. I found that I slightly preferred the 21 w/5" BP slightly over the 15. Not by much though. The 15 is an excellent choice.
I've yet to switch the 5" off the 21 in exchange to put the 6" BP back on. I prefer it this way.
Thank you to all who have responded to this thread to make it interesting.

Glad to hear that. Do you think that the 5" plate and 6" pads run as smooth as the 6" plate and 7" pads on the 21?

[expdetailing]

Glad to hear that. Do you think that the 5" plate and 6" pads run as smooth as the 6" plate and 7" pads on the 21?

Yes, I didn't notice a difference in vibration. The 5" seems to stall less than the 6" significantly. If you already have the 21, I believe the cost of aa 5" BP is justified. If you don't have the 21, go for the 15 and save some money.

[jarred767]

With the 5" BP and 5.5" pad on the 21, (with the KB washer mid) I see very little stalling. I haven't used a Flex yet to compare it, but this Rupes setup works very effectively for me doing corrections. I may buy the Flex down the road just because, but right now, I just can't justify it.

[Moldavite]

rupes 21 + 5" BP + 5.5 pad!!!
sound good

[VISITOR]

rupes 21 + 5" BP + 5.5 pad!!!
sound good

or Flex 3401 + 4", 6", 4 3/8", 5.5" BP + 4"-6.5" pad!!!

[Moldavite]

or Flex 3401 + 4", 6", 4 3/8", 5.5" BP + 4"-6.5" pad!!!

even better...lol

[RPM_BR]

I have the 21 with a 5" backing Plate and I love it.

Me too. I use the same combination, the 21 with 5'', and the Flex with 4 3/8, hybrid pads most of the time.