I'm mudflap curious, educate me please

[roubaixtuesday]

Winter is coming and I'm mudflap curious.

Commuter and tandem both have full length mudguards, but I see some folk also fit dangly bits too - mudflaps - both front and rear.

Am guessing
- front ones protect drivetrain better?
- rear ones are for others benefit behind.

So
- am I right, or are there other benefits?
- how do they fit to existing guards?
- Are they worth bothering with
- any recommendations?

 

[si_c]

Basically what you note above. The long flaps, particularly at the front stop spray from the front wheel onto your feet and bottom bracket and the rear ones are largely a courtesy for anyone behind you.

I've got some fitted to my winter bike - I use Kinesis Fend-Off mudguards with RAW mudflaps. RAW have a good list of common mudguard brands and you can select the ones which fit those you have best.

The nice thing about the RAW guards is they are retro-reflective so light up really well for drivers behind at night.

Edit to add: Most mudguards come with a smaller flap at the bottom which fits with a single, often plastic, screw (certainly all the ones I have had did). The replacement guards just fit into that - I'll get a photo of mine taken to demonstrate, it's also a reminder to me to re-fit them for winter.

 

[Big John]

Never had front extensions but when I belonged to a club it was really frowned on if you didn't have an extension on the back in winter. Usually a piece of old mudguard pop rivetted to the main rear mudguard. If you didn't have one you were banned to the rear of the group 😭

 

[Hacienda71]

Yep a lot of clubs insist upon or encourage mud flaps.

 

[biggs682]

Or just use a piece from a plastic bottle

 

[Moodyman]

Making your own is more effective as you can choose size and material. Look for material that is stiff enough to resist fast downhills but has enough give if you roll your bike up/down kerbs.

Damp proof material or laundry detergent bottle are commonly recommended.

I’ve seen some of the retail flaps too flappy on downhills or into stiff headwinds.

 

[matticus]

...
I’ve seen some of the retail flaps too flappy on downhills or into stiff headwinds.

I've never been brave enough to look over my shoulder at high speed - nor to closely draft anyone in the wet at 40mph - so I still wonder if a flap bending backwards in the air-flow is a problem; won't it provide MORE protection?

 

[Moodyman]

I've never been brave enough to look over my shoulder at high speed - nor to closely draft anyone in the wet at 40mph - so I still wonder if a flap bending backwards in the air-flow is a problem; won't it provide MORE protection?

A good front flap should be an inch or two lower than the lowest chainring (usually outer). I’ve seen several, on others bikes, bend horizontal, thus throwing water into the drivetrain.

 

[oldandslow]

Very popular in Audax events too, since informal groups tend to form and it's nice not to get sprayed by the rider in front.

 

[cougie uk]

Flaps make a huge difference. These guys will do a flap that suits your bike and they also have reflective ones too.
https://rawmudflap.uk/

 

[wakemalcolm]

The butchered white round fairy liquid bottle used to be the weapon of choice at my club in the 80s. Fortunately my ESGEs came with a flap already attached.

 

[andrew_s]

Rear mudflaps only need to be 2"/5cm wide, but should reach to within 4"/10 cm of the ground. Many are too short to be properly effective.
As a rule of thumb, if you can see the tyre of the chap in front under the end of their mudflap, you should consider dropping back out of firing range.

Front mudflaps have to deal with what the tyre splashes sideways out of any puddle you ride through as well as what spins off the centre of the tyre. To keep water off your drivetrain and feet, a flap should be maybe 6"/15 cm wide, and reach to within 2"/5 cm of the ground.

 

[Richard A Thackeray]

Basically what you note above. The long flaps, particularly at the front stop spray from the front wheel onto your feet and bottom bracket and the rear ones are largely a courtesy for anyone behind you.

I've got some fitted to my winter bike - I use Kinesis Fend-Off mudguards with RAW mudflaps. RAW have a good list of common mudguard brands and you can select the ones which fit those you have best.

The nice thing about the RAW guards is they are retro-reflective so light up really well for drivers behind at night.

I have front & rear RAW flaps on my work-bike, they’re excellent
Being so low, they’re the first item to catch vehicle headlights (or low sun)

 

[Webbo2]

I found one of those ass saver guards when walking the dog. So I took it home cut it down and attached to the bottom of my mudguard with nut and bolt. Works well.

 

[Drago]

I found one of those ass saver guards when walking the dog. So I took it home cut it down...

Poor dog!