I see others have chimed in with some other aspects of adjustable bars that I didn’t have time to write. I looked around the Internet today and found this Smith Worthington blog article http://blog.smithworthington.com/ that explains some of the options and limitations of extended and adjustable bars. Contrary to what SW said about losing those screws from the Wellep bars, you can find a Phillips head version at Lowe’s (in hardware, in the blue cabinets) that’ll do. Or you can get the exact slot head stainless steel one from Fastenal dealers. It’s a metric size, but I don’t recall what it its. I took one to Lowe’s, used those bolt and screw size socket things than hang on the uprights near the fasteners, and figured out what size and tread. I bought a couple Phillips head ones at Lowe’s for temp use and then got the real thing from Fastenal in under a week.
I concur with the person who said that adjustable bars are bulkier. The Wellep bars are the least offensive in that respect. The Whitman threaded Adjustabars are the worst I even encountered, particularly when set all the way bar, because they aren’t recessed at all.
The Wellep bars are shown on saddle trees here: http://www.wellep.com/Wellep%20Eques…%20System.html The stirrup leathers can to slip off them very easily if the saddle ever heads uphill and you happen to have little or no weight in the stirrup iron at that particular time. That’s my only complaint with them.
The Coterell slider type are very long, and the rear attachment point for them, if they are 4 position, is probably too long for anything other than a cutback saddle. They might be fitted onto a larger dressage saddle, but I would wager that the back of the bar will be uphill, and also very snug against the saddle, and that will make the back 2 positions hard to lock into, and also will make more bulk under the rider’s thigh. The straight end anchors to the front of the saddle, and the big paddle shaped end attaches in the twist area.
https://german.alibaba.com/product-t…143908443.html
The Bates bar looks interesting. It has a nice upward hook to help keep those stirrup leathers on the saddle. That’s one of the best ideas yet.
https://www.batessaddles.com/wp-cont…stablebar3.jpg