Boxerworks.com

1984 R100
My supply of OEM straight oil filters is now depleted. I picked up a new one from the stealer, and see that is now one of those split filters. Looks like a large reduction in filter capacity. The press together center seal looks suspect as well. Am I better of with an aftermarket straight filter? Are there any that are known to be quality built. How about the "HIflo" brand?

The most important thing is to make sure its the proper filter for the bike. I see there are two different split filters available. Depends if you have an oil cooler or not. My 81 R100RT has the oil cooler and uses a split filter and has over 170,000 miles on it. I have never used an aftermarket filter. I bought a Fram one time but refused to use it due to the little fuzzy's stuck to the paper element. Looked like a cheap sweater I had years ago!

As indicated, nothing wrong with the newer style oil filter. Likely, there's more than enough filter surface, even with the reduced area. One positive with them is they're less likely to collapse since the paper section is shorter for each part and thus are stiffer. Generally this doesn't happen, but has been reported to happen with the one-piece.

Kurt in S.A.

The straight filters are available on the InterWebs from Max and Hucky, but they aren't in a BMW box anymore. Still a Mann/Mahle filter. If I have to order other parts, I'll get a filter also. But if I don't, I'll get a split filter from the local (car, as the nearest bike dealer is 200 miles away) dealer ordering by part number. What I pay in sales tax is less than I'd pay for shipping, and the price is pretty much the same.

I've only used a bendy filter once and didn't much like it. The plastic hinge/seal between the sections means the filter doesn't want to sit straight in the filter tube which makes them a little more awkward to fit. Inevitably there is less filter area which might mean more oil bypasses the filter. That happens anyway every time a cold engine is started but more pressure drop across the filter won't help. Assuming you don't need a bendy filter the only plus point is they are stronger but don't imagine that makes them immune from collapse as I've heard several reports of them doing just that. The bottom line is bendy filters are a less than optimum compromise imposed by the physical access on some airheads. No need for the rest of us to use them as we already have one compromise imposed on us by other airheads in the shape of the $2000 O ring.

I've used Hiflo filters for nearly 10 years and only had one collapse

To be fair, I was so sure the fault was mine and not the filter, I was happy to carry on using them and have gone through another half dozen without further problems. As for quality of the filter media, short of a sophisticated lab test procedure you are not going to know. The manufacturers web site provides some reassurance as they are obviously far from a back street outfit and claim TUV approval.

http://www.hiflofiltro.com/

Amazon seems to carry a nice selection of filters, both Mahle OEM and a couple of after market suppliers. I

PAS wrote: My 81 R100RT has the oil cooler and uses a split filter and has over 170,000 miles on it.

That's way too long of a service interval, PAS. I change my filter every 5,000 k's.
No wonder your bypass spring broke!

You may be right! It's amazing the oil lasted that long too!

I also have used Hiflo filters for years, only about 5 years tho. Hiflo makes only one filter for our bikes. The HF 161 and it is for the non-oil coolers. It is not bendable. I forget the source but they had really cheap prices so look around.