Is the SL-R3000 compatible with Shimano Tiagra 10-speed components?

No — the SL-R3000 is 9-speed only. Tiagra is 10-speed with different cable pull. Using a 9-speed lever with a 10-speed derailleur will result in imprecise indexing.

Can I use this with a 9-speed MTB cassette on a road bike?

Road and MTB 9-speed use different cassette spacing, so mixing is not straightforward. Stick to Shimano road-specific cassettes (CS-HG400) for use with Sora road components.

Shimano

Shimano Sora SL-R3000 Shift Lever Flat Bar Road

Name: Shimano Sora SL-R3000 Shift Lever Flat Bar Road
Brand: Shimano
SKU: ESLR3000DPA
Price: 7370.00 INR
Availability: InStock
Author: InstaSport Editorial

₹7370.00

Description

SHIMANO SORA - RAPIDFIRE PLUS - Left & right Shift Lever - Flat Bar Road - 2x9-speed SHIMANO SORA SL-R3000 shift lever provides reliable and intuitive shifting for flat bar road bikes. The RAPIDFIRE PLUS right shift lever allows riders to downshift three gears in one stroke and SHIMANO's OPTICAL