anyone out there got upgraded brompton suspension? I fancy a change.
thoughts or evidence would be appreciated
Realistically optics is the only thing what most "tuning" suspensions on the Brompton achieve. In fact the factory suspension does a pretty good job. If you mount a camera pointing towards the suspension block you'll be surprised. The only downside is that with riders of average weight (and even more with heavier riders) the (former) standard block is too soft, eating up your pedal power to a (small) degree. Depending from the age of your Brompton problem and solutions are different:
• Brompton up to 2007: Put a jubilee clip around the suspension block.
• Brompton from late 2007 until 2017: There's a standard block and a "hard" block available (or: has been). The hard block is much preferable for most riders.
• Brompton since 2018: Only one type of block available, in the middle between the former standard and hard blocks. For my taste no need to change anything. You can however if you want to have it harder change it for the Joseph Kusoac one - this is much harder, good for effectiveness of the drivetrain, less for comfort). The B75 has a white suspension block - no idea if it is different. The Chpt3 has a red suspension block. Rumors say it would be harder, no idea if that is true.
You can upgrade any Brompton to any of the newer blocks if you wish so. Spending money on non-factory blocks (apart from the Kusoac one in rare circumstances) does not have any notable positive effects apart from optics and is thus not worth it. I would recommend not to trust people who state different claims and massive positive effects - having spent the money already they seem to be a little biased that there must be an effect to justify their spending.
